Drowned.

The 3 continued their climb the next day, making their way up and fending off whatever threats came their way, yet none of them were calm that morning, for the memory of what they read of the Guardian of Black Waters still lingered in their minds.

"At least the trees are getting smaller, I can see the sun rising now" - Castoria said as she looked up at the rays of sunlight that passed through the leaves and branches of the trees.

"It is…" - Mash answered.

"Mash, what's wrong?" - Ritsuka asked as he put his hand on her shoulder. The girl was lost in thought, and it was worrying him.

"It's nothing Senpai, I'm just thinking about this place. It seems like no matter how much we find out about this place, more things just keep showing up" -

"Well, not surprising. We've only been here for 8 days after all, barely more than a week. Besides, it wouldn't be a Singularity if there weren't strange things in it" -

"Then I have a question for you two…" -

"What is it, Artoria?" -

"Is it normal in Singularities to find drowned bodies floating in the water?" -

As soon as they heard what the Caster said, they rushed to see what she meant, and what they found was terrifying to say the least. In the distance, barely covered by a thin mist, several bodies floated on a lake. Despite their differences in age, gender and clothing, the one thing all shared was that they all had their faces sunken into the water.

"They're not recent" - Mash said as she took good looks at the corpses - "They've been here for a few months at least" -

"Wait, how can you tell that?" - Castoria asked as she slowly turned her head to Mash.

"Holmes gave me a few books about how to be a detective, and in one of them came how to identify for how long a body has been dead" - the Shielder said.

"Leaving that aside… I feel like we shouldn't get near, there's something strange about this whole situation" -

"Aside from the dead bodies?" -

"Yes, aside from the dead bodies" -

As Ritsuka finished answering to Castoria, they felt the ground shake as something started to move underneath the water, only for a giant tentacle to appear seconds later, grabbing one of the bodies and dragging it deep into the lake.

"Let's get out of here, and fast" - Mash said as she took Ritsuka and Castoria and started to run with them, yet before they could even start moving, tentacles rose from the ground, grabbing them and pulling them towards the lake.

The trio tried to cut their way out of the grab, but whatever was pulling them quickly showed more of its tentacles and stopped them, trapping their limbs as they were sunken into the lake.

The dark depths stopped them from seeing what was around them, making the situation all the more terrifying, yet Castoria, seeing as how Ritsuka and Mash were in danger, quickly took action. A blue light enveloped her body, and she went from her second, to her third form in an instant, summoning several swords to shoot at the tentacles, piercing them and making them release them.

"Master, Mash, quick!" - the girl yelled as the two started to swim as fast as they could. Unlike Castoria, they were humans, and still needed air to breathe.

The beast retaliated against the attack of the Caster, bringing forth more and more tentacles to try and crush her, yet the girl made a quick escape, returning to the edge of the lake just as Mash and Ritsuka did.

"Are you both alright?" - she asked as they coughed.

"Luckily… Thanks for that Artoria, you're a lifesaver" - Ritsuka said as he got back up on his feet.

"That thing… Whatever it was, its energy signatures were way out of the normal" - Mash said as she summoned her shield - "And…" -

"It's coming for us again. Master, think you can use the power of another Servant to help us here?" -

"Y-Yeah, just let me focus and…" - as he summoned the power of the Shadow Servants, his clothes changed to the ones worn by Cu Chulainn, together with the spear Gae Bolg - "Alright, this is gonna hurt later but right now…" -

The ground beneath them started to crack and tentacles started to come out of the shattered earth, first 1, then 2, then 10, then 50. After that, its head emerged from the lake.

Advent: Mystery Island Entity "A"

Terror of the Blackened Depths.

Altered Kraken.

The mythical Kraken, but different from the one in norse myths. The one that the trio was facing down had a darkened body with several strange sigils all across its body, its two eyes shining in red fury as it prepared to attack them.

It quickly swiped with its tentacles at the 3, but now being on land instead of underwater, they had more room to dodge the attacks of their enemy. They managed to dodge the hit while slowly getting closer, careful to not get hit by any attack that the creature tried to use against them.

Castoria used the crystallized swords that she had summoned to pierce the tentacles of the Kraken, before using her Marmyadose to cut them clean off and making her way to the face of the beast.

Seeing this, the Kraken retaliated by unleashing a wave of poisonous gas that quickly started to fill the area and close itself around Castoria, but she managed to escape, drawing the attention of the Kraken towards her.

Using this as an opportunity, Mash approached from the right side and Ritsuka from the left, both jumping and throwing their weapons directly at the creature, hitting its face and spilling its black blood all around the terrain.

As soon as the blood touched the ground, they saw how it slowly started to blacken and die, the plants rotting in a matter of seconds. Could this be the Guardian Of Black Waters?

There was no time to think of that however, as they had to deal with the Kraken first, they would get their answers later.

After being struck by Mash and Ritsuka, the Kraken used all of its tentacles at once to launch a devastating hit which created a massive shockwave, sending all 3 of them flying.

Just after that, it unleashed more of its toxic breath, yet this time Mash jumped in front of Ritsuka and Castoria to protect them, summoning her Noble Phantasm, Lord Camelot, to block the hit while the other 2 got back up on their feet.

"This thing is not going to go down easy like this" - Ritsuka said as he held the spear tight in his hand.

"Next time, we're going to be a bit more careful around lakes with drowned bodies floating in them" - Mash said as she held Lord Camelot with all her strength.

"This thing is meant to resemble the Kraken, but it's nothing more than puppet controlled by magical energy, and I think I can disrupt that flow" - Castoria said - "Master, Mash, I'll need you to buy me some time, I can get rid of this thing" -

"Really? Then we'll give you as much as you need. Make it count Artoria" - the Shielder said as she smiled at her friend.

"Of course. You two, be careful" -