There was nothing better than a day in the sun. It made the water warmer, the grass grow and the animals around it swarm for a cool place to sleep their exhaustion away.

It also brought a certain man to Merlin's lake.

He heard a shriek, high and very unmanly in its execution. Merlin heard the girls below him laughing, bubbles frothing up as Merlin sent another knock to the wood at his side. He bowed for his audience as another unmanly squeak came from above, only to dart to the side when something dashed down next to his face. It came again, the oar from the boat above following the shadow Merlin made in the water around and around until Merlin saw the man above fall over his own feet and appear before him. They came face to face, Merlin marvelling at having the man so close. Usually he saw him from afar, that head of blonde hair drawing his eye the moment Merlin spotted it through the trees. Up close it looked like tendrils of gold, like a stream of necklaces drifting in a breeze.

The man was startled, first from the fall, and then again as his eyes made out Merlin in front of him. His eyes were comically wide, mouth bloated as he tried to hold in the air above. It made Merlin smile, his hands coming up to grasp those bloated cheeks and plant a kiss on the man's mouth.

The reaction sent Merlin sniggering over to the girls, the man flailing and scrambling as he pushed Merlin off and grabbed around for air and his boat. The man made it back in with nothing else hindering him. Nothing pulling him down or biting his supple flesh. The man knew he was lucky to have gotten back to his boat in one piece, the curses he sent to the waters below mild in comparison to some Merlin had heard. He was grateful, but didn't want to show it. A thing that had Merlin fascinated, elated and darting to the reeds so he could see the man, Prince Arthur himself, shout at no one in the water.

Such a funny human.

He wondered why the prince even came on to the water. It wasn't like there wasn't another way around the water. Sure, it took longer, but the trees surrounding the lake were safer than the creatures that lurked beneath the murky waves.

Most people avoided it, Merlin even knew of a knight someone from a nearby kingdom had placed somewhere within the trees. He warded off those who thought it a good idea of crossing with tales of monsters, men and woman alike, they weren't too picky, would fall to their teeth should they ignore the knight's warning.

Someone like Prince Arthur would surely have heard about the monsters. If he thought they were just tales he would have known after his first visit that they were anything but. Yet, time and again he came to the lake, still crossing, still refusing the other path, and it made Merlin more and more curious each time he did.

'Do you think he's stupid?' he asked his mother that night. 'He looks it. Maybe he's the lame prince of Camelot.'

'Does it matter?' his mother wasn't one for listening to tales of Merlin's prince. She had warned him the first time he let the man go that it would do nothing but hurt him in the end. Whether that be Arthur luring Merlin into a trap, which had actually happened to one of the girls in their lake, they took a fancy to this guy, let him go, watched him every time he came back and the guy grew smart to it. Decided he wanted to make an example of her kind when they ended up killing someone from his village. He used her affection for him to lure her into a net, skewering her in front of the other merfolk on the shore while asking how they liked being the victims. Merlin knew his mother didn't want that happening to him, she was rather kind hearted like that, a trait that wasn't often found in their kind.

'Yes, it does. I mean, if he's stupid then I get why he keeps coming back. He probably doesn't even remember crossing the next time he decides to go out. But what if it's something else? More and more people have been trying their luck of late. Maybe it's a sign.'

'Maybe.' She swam off, her patience for Merlin's wonderings gone.

He pushed all thoughts to Arthur to the side for now, having better things to do like sunbathe and hunt to ponder about why he came. For all of three days. He was digging a gold necklace that had got caught in his scales when a shadow made it hard to see. Long and thick, there was only one thing he knew that made that shadow.

Fins darted past him as he left the necklace alone. The girls had already started circling, the smell of fresh meat high in their noses. He joined them, scenting the occupants himself to make sure it wasn't his idiotic prince back for another jaunt about the water.

No, the people above were unfamiliar, which made them fair game. The girls floated along quietly, Merlin tagging along the back as the girl who got there first made a plan.

She took the front of the boat, slowing its passage and making sure there was nothing within reach to help the man to shallow waters. The oars were the next to go, each one digging in harder to try and get the wood to move under the girls strength. They drifted slowly to the bottom of the lake, Merlin knowing that someone would get them, along with the boat, when they were finished eating and put it back at the edge of the lake for their next victim.

The man above was trapped now, with nothing but the deep awaiting him. Or so they thought. The girl had went up, not bothering with niceties in favour of dragging him neck first to her teeth. Yet no sooner had she surfaced was she cast back down, the crackle of magic heavy in the air.

The boat moved on its own, not needing oars and certainly paying no mind to the other mermaid who was trying to stop it. A unanimous decision was made as the next girl was sent down as well, all of them turning to Merlin with expectant scowls. Ever since he was small if it had magic it was Merlin's problem, something he was always pouting about to his mother. Just because they were dangerous and he had magic himself that didn't mean he had to be the one to deal with it. It just wasn't fair.

Still, with barely a blink Merlin had the boat stopping again, clambering up the side to face his would be sorcerer. There were gasps- there were always gasps when people saw him- and an underlying thrum of magic as the man prepared another assault.

'Don't bother,' Merlin warned, making sure his eyes flashed dangerously.

It had its intended effect, the man cowering away from him and crowding, arms stretched, towards the back. He didn't look too scared however, not in the way they usually were. Even with magic they often ended up begging for their life after a while. Yet this man looked like he had already accepted his death, was embracing it with open arms, it was only- damn- the life he was protecting behind him that had him fighting.

It was a boy, no more than eleven in age and standing unafraid, almost curious, behind the man's arms. Now, Merlin knew his kind was heartless, he often didn't care if women said they had children waiting at home or waiting for them on the other side. More often than not he would make kinds to get them next before dragging whoever it was to the deep. But that was all talk. When a child did come to their lake, they often had a change of heart. Especially when they were, more often than not, more useful to lure people than dead.

The man was lucky, that was all Merlin would say later when his mother asked what happened to the people crossing.

The girls had already fetched the oars, one of them peeking up behind the man to see why Merlin hadn't made the kill. They put them in the boat, sinking back down and letting Merlin take over.

The man looked like he couldn't believe his luck. He kept his hands over the boy, shielding him the whole time Merlin dragged the boat over to the shallows. When it hit gravel and Merlin went back to the water he heard a few passing words about the gods being favourable today before leaving all thoughts of the boy and man behind in favour of luring a hunting falcon that had been circling their waters for an hour now. A hunting falcon almost always had an owner, which meant easy meat.

The weeks passed after that with Arthur returning to the lake a few times. He rowed too and fro, subjecting himself to Merlin's teasing again and again for some purpose or another. Merlin was almost curious enough, as he came a third time that month, to go up and ask Arthur what was so important it couldn't wait ten extra minutes. He'd heard rumours, whispers and seen for himself some of the carnage that was left in the larger waters. Something hostile was on their lands, more, it knew what they were and how to capture them- something that wasn't an easy feat if they weren't a lovesick mermaid.

But he stopped himself on the basis that it was one thing annoying Arthur and a whole other to show himself to the prince. So he kept himself to the waters, contenting himself with taking oars and upsetting the boat.

He thought Arthur had come again when someone told him to take care of the boat. It was rowing rather fast, much different to the strong sure, steady strokes Arthur used. There was that crackle of magic there too, helping the boat move more freely in the water. It was no wonder the girls had sent him up.

Oh.

He stopped halfway up, recognising the wide blue eyes that looked down, almost directly at him. It was the boy, the same one Merlin had helped to the other side a few weeks ago.

He darted to the reeds to make sure, seeing the same blue cloak and dark hair that made up the curious unafraid human. There was something different about him, that had nothing to do with his new guardian. A sickness seemed to be hanging over him, almost gone now but still lingering around the boy.

The man travelling with the boy now pulled him back from the edge, murmuring warnings that carried over to Merlin's ears. 'Stop looking. You'll attract attention and these things will kill you boy.'

The man could have been talking to a wall for all the good it did. The boy, Mordred, as a few more muttered words made its way over, seemed to be looking for something, or just fascinated with the lake he was rowing across. He pulled back from his guardians hands every chance he got, leaning over the side or scouring the reeds, looking straight at Merlin every time he found him.

It became a sort of game, Merlin testing the boys perception more than anything. He dove and hid as many times as he could but Mordred always seemed to know where he was. It was fascinating. He'd never met a human with such awareness before, it made him wonder how he did it, what it was that told the boy where to look.

Nevertheless, it had Merlin impressed. So much so that he sent some of his own magic the boy's way, pushing away that last lingering of sickness. Mordred looked like he'd had a religious experience, stuck still in his seat so much that the man guarding him had to visibly lift him up to carry him off to the woods.

He gave a half hearted wave to Mordred, hoping this was the last time they would meet. He doubted the girls would be so forgiving if he started bringing more off limits meals to their lake, and had no want to see the day come where they would forgo their no children rule and have him for supper.

The days turned to nights, and before long Merlin was seeing Arthur creeping around the shallows again. It was one of the last summer days of the year, Merlin deciding to spend it on a grassy bank just shy of the treeline. He watched as today, Arthur ignored the boat in front of him, seeming to find what he was looking for and going back into the trees.

A rustle sounded a few metres away, Merlin rolling his eyes at the lack of tact Arthur had. Of course he wasn't here to cross today. Why would he when the sun was out and there were half human women with no shame and no clothes on their chests. The girls a few feet from him sent him withering looks, saying without speaking that they knew Arthur was there too, and they weren't impressed.

Turning on to his front Merlin ignored the heated looks and set about finding Arthur's feet in the bushes. He started when he saw just how close he was, his theory about the prince being stupid growing more believable every second he lay there. If that wasn't bad enough he had someone with him, a female someone from the smell of it. She at least, had some stealth, making no noise on the forest floor as she knelt next to her prince.

'Told you,' Arthur said, a smug note in his tone.

'That's incredible.' Her voice didn't rise higher than a whisper, there, again showing stealth where her companion did not. 'Uther will be furious.'

'Indeed.' There was a rustling, something being pulled from a sack and the sound of pages turning.

'Tell me you didn't steal that from Gaius.' The silence said it all. The pages stopped, Arthur huffing a laugh that ended on a rather defeated note. 'Bad news?'

'Extremely. They're mermaids.'

'Maids? Don't know about your eyes but that one doesn't look very female to me.' Merlin hid a smile at the appreciative note in the girls voice. He may have even flicked his tail a few times for her pleasure, he knew how pretty it was to look at after all.

'Well- folk then. And apparently they're very deadly. Not only are they strong, fast and charming, but they have singing voices that can enthral anyone that listens to them. They also eat people.'

'Lovely.' A pause, 'Does it say how to kill them in there?'

'No.'

'Uther's not going to be happy.'

'No doubt. He'll probably have me leading knights down here tomorrow to kill the beasts.'

Merlin considered splashing Arthur for the beast comment, but this information was the most he'd heard from this prince. It was interesting to note they hadn't known what it was hiding in the lake. Definitely explained why there wasn't mob after angry mob trying to fire arrows into them. Very interesting that someone had managed to see them anyway, and document them. It also told him that this Arthur wasn't as stupid as he looked.

'What are you going to do?' the girl asked.

Silence. 'Nothing. We don't tell father. If these creatures really are as dangerous as this book says we don't want their ire. It says they can take down a boat full of people in seconds, imagine what they can do to a kingdom. All they'd have to do was get into the waters. The ones that flow all through Camelot, and we'd be done for.'

There was a thought.

'I won't tell. Nor will I tell about the other reason you want to keep Uther from finding out about them.' The seriousness was gone, teasing taking its place. Whoever she was she was close to Arthur, which kind of had Merlin wondering about her. She could probably tell him tonnes of stories about Arthur. What he was like when he got back to his princely things, what he liked to eat, drink, listen to...

'Which is?'

'Hmmm, topless girls and pretty boys. I wonder why you-'

The leaves rustled, Arthur blowing his cover completely in favour of messing around with his companion. 'I'll have you know I'd never even seen one before today. They've never sunbathed before now. So shut up.'

For that last comment Merlin decided to have some fun with Arthur the next time he came to the lake. He was honestly hurt that Arthur lied to his lady friend. He'd gotten more than a good look at his kind, and more than once too. Merlin had even kissed him. So, the next time he saw that blonde head he perched himself on the side, laughing lightly at the shocked fright on Arthur's face. 'I know we're not exactly memorable. But hopefully you'll ingrain my face this time into your memory your highness.' He had him by the lips before the prince could even utter a word, enjoying the easy way Arthur gave in, and even more when he dragged the man underwater. They stayed there, Arthur struggling in his tight grasp, until all the air had left his lungs. Making sure he hadn't killed the prince, Merlin left him on the shore.

He didn't return for a month.

Instead, when the boat came over his head it was another familiar face peeking down. Mordred.

His hopes to never see the boy again went unheeded by whoever was listening. Mordred was back again, and, like last time, had seemed to abandon his carer in favour of another. Three in fact, with more circling the edge of the lake. Merlin saw a few of his comrades drag down those that veered too close to the edge, which begged the question of why these three thought it a good idea to go on the lake when the other option was far safer.

He went over for his own share, his kindness to the boy extending again to this passage. When he was done, the boat was still there, stopped in fact, right in the centre of the lake.

Mordred was looking over at him, no revulsion or fear on his face. Instead he smiled, actually smiled at Merlin despite the fact he still had human on his face.

The others in the boat were less than pleased to see Merlin, especially when he swam over and pulled himself up the side. They looked about to fall off the side with how they were trying to get away from him. Mordred on the other hand had no qualms about lifting his fingers and pushing them through Merlin's hair. He looked like he couldn't believe Merlin was there. Even his magic was happy, bouncing gently against Merlin's like feet dipping in a wave.

'You should probably leave,' Merlin warned. 'I don't know how many more times we're going to let you cross here.'

The others nodded, already knowing the fate that awaited them. Mordred strayed their hands however, when they reached for the oars, glaring back at them like he was the adult and they the children, before turning to Merlin again. He poked his head to look down the side of the boat, his hands venturing from Merlin's hair to his skin and finally his scales.

He let Mordred look his fill before retreating back down. Almost as soon as he did the boat started moving again, the adults probably winning whatever power struggle had been going on. Not that it stopped them from coming back. Merlin had half a mind to kill the boy himself if he was so stupid to think he would get away with this forever.

Yet there was something different about this visit. There was a smell in the air, more humans coming down. As Merlin listened he could hear the adults on the boat panicking amidst victory cries. But more than that he could hear Mordred himself, plain as day like he was right next to Merlin and not a whole ten feet. It took a moment for Merlin to realise that it was coming from inside his head. Another sharp 'Emrys!' sounding before the other humans made themselves known.

They crashed through the trees with crossbows and swords flashing silver in the sun. Knights. Whoever Mordred was with they were no friend to this kingdom, the knights opening fire and hitting one of the men in the boat, sending him over and into the waiting teeth of the girls below.

Merlin remembered what Arthur had said about the knights not knowing what was in the lake, wondering if the boy above was worth exposing them just to get him out of the firing range.

'Emrys!' came again, Mordred sounding desperate above. Merlin supposed he too would be begging if he was in that situation. No one wanted to die. Not really.

It took little time to swim up and under the boat, the girls lying in wait below it for Merlin to make the grab so they could get the meat. Mordred was easy to pluck out, Merlin making sure the boat tipped enough to look like he fell. He warned the girls as he swam away not to make it too obvious what they were. He had to give Arthur some credit for the idea of keeping themselves a secret. It would certainly make hunting all the more easier.

The men were disposed and boat swaying empty as Merlin broke to the surface in his hiding spot. Mordred was spluttering, clawing desperately for the bank and air, Merlin letting him get a handhold and nothing more. the knights were still at the edge of the forest, scratching their heads and wondering just what the hell they'd seen.

It took a while for them to leave. They seemed to be living in a distant hope that the people had merely fell and would surface any minute. Yet the hours passed and no sign came. Eventually the knights called it a day, Merlin hearing them ask what they were going to tell the king when they got back as he turned to his little problem still clutching at his arms.

Mordred had stopped struggling for a while now, content to sit calmly in the circle of Merlin's arms. He even dozed off for a while, Merlin smothering the urge to drown the little troublemaker when a thought on how cute he looked passed through his mind.

With the knights gone, Merlin helped the boy back onto the bank, telling him to wait there and even getting him some guards, while he went to go search for someone to take him.

The answer came on the fourth stream he searched, a small band of men were huddled by a fire, many of them harbouring the same three pronged tattoo the man he'd first seen Mordred with bore. Better, they had stories very much like the one Mordred had just escaped from. Stories of knights and close misses that had Merlin leaning closer to hear clearly. It got better still when one of them unwrapped something from his cloak, something Merlin recognized from both memory and magic. It called to him, telling him to grab it. It was strong enough to have him crawling halfway out before he realised he couldn't exactly just walk in and get it.

But then, well, Mordred came to mind, and a devious plan with it.

He got back to the lake in record time, Mordred happy to see him again up until Merlin told him he'd found his humans. The boy didn't speak, but then he didn't really have to with that glare on his face.

'Don't be like that. You belong with humans, we'd probably eat you after a few days if you stayed here,' Merlin reasoned. Mordred pouted even more, Merlin thinking this was just the right time to put his plan into action. 'Okay, how about a compromise? I promise, no, we promise, that you can come to our lake at any time you like, day or night, no matter how old you get, and no one will hurt you. Sound good?' That piqued his interest, Mordred smiling a little to himself with the idea. 'But, there's a condition, you have to get something for me.'

That something had Mordred complying all the way back to the human camp. He didn't run off, throw a tantrum or even try to negotiate with something else. Merlin thought this was the start to a wonderful friendship. If he didn't know any better he'd say Mordred was actually wanting to do something nice for Merlin, that want holding strong even after he learned what it was that Merlin wanted.

'That.' Merlin pointed, the crystal shining slightly between the rags. 'Bring me that.'

Mordred glared at it slightly, but nodded anyway, hopping out onto the bank and wringing his cloak out. 'Where should I bring it?'

Merlin thought about that. He couldn't have the boy bring it to the lake, he didn't want to risk the boy being seen either by the knight or being followed by one of the adults and killed just as Merlin had promised him immunity. He remembered this other little place, somewhere his mother had shown him when he was a child. It was a pool, somewhere she had met his father at. 'There's a place not far from here. There are giant statues and a gap between them. They lead to a pool where I'll meet you. Don't be too long.'

Mordred nodded, tottering off back to the adults like a wounded child and leaving Merlin in slight awe at his acting skills. Not wasting time, Merlin dived, swimming easily to the pool he'd said and waited.

He didn't worry about Mordred as the hours went on. The boy was powerful, that much was known more than just the touch of his magic. Despite the fact it thrummed like nothing Merlin had ever felt there was also the way the others had treated the boy. The first time had been like he was to be protected, and, looking back, Merlin was beginning to wonder if that was at all familiar affection or something else. If he was powerful the man would have probably been charged with protecting him. An interesting thought. Then there was the other man on the way back. Despite his attempts Mordred had ignored him in favour of looking over the side. Surely, much like the humans he'd just disposed of, if Mordred had just been a simple errant child they could have easily put him in his place? Yet, they didn't. They let him do what he liked, to a point.

Maybe it wasn't just luck that had Merlin sparing Mordred.

He came just before nightfall, the small brush of magic touching Merlin's own the only notice he got before two little feet were dipping in the pool. He handed the crystal over when Merlin prompted, looking glad to be rid of it.

'They say I'm meant to master it.' he said after a while.

'They?'

'Alvarr. The man in the boat. He wished for me to use it to unseat Uther.'

Uther. Arthur's companion had mentioned an Uther, and since Mordred said unseat he guessed the man was Arthur's father. it was an odd thought thinking Arthur had a father. Merlin's kind didn't often put family to meat.

'I doubt you could have done that with this.'

'You know what it is?'

Merlin nodded, remembering something similar his mother used to own. 'It's a seeing stone. They tell the future, well a possible future.' Mordred's interest grew, the boy inching closer to the crystal like he could activate it if he looked hard enough. 'You won't see anything. It only shows you when it wants to, and only ever your own future. Unless you were meant to unseat Uther at some point in your life this crystal is basically useless.'

'So it isn't a weapon?'

Merlin shook his head, wondering what was going on in Mordred's head. Was he happy about it being useless? Upset that he risked his life for something so trivial? Merlin didn't know, he couldn't tell through the blank line and wide blue eyes and it was driving him insane. If there was one thing his kind prided itself on it was reading people, how else were they to lure prey if they couldn't.

Needing some time to think Merlin sent Mordred off with warnings of the others getting suspicious if he wasn't there when the crystal went missing. He expected a fight, from the reluctance Mordred had already shown it wouldn't be that far a stretch. But something obviously clicked in his mind since he was getting up and leaving once he made sure he could go visit Merlin whenever he wanted.

'Of course, I promised you didn't I?' Merlin grinned. 'Besides, that Emrys you were calling for will probably want to see you again.'

He chose to ignore the confused frown on Mordred's face, his head already battered enough with trying to read this kid. Hopefully the next time they saw each other would be less confusing.