Once again, this just poured out of me. I got home from work, sat down, had a sandwich and lost several hours. Anyway, disclaimers: I know nahtheeng... I owns nahtheeng... I don't own the copyright, yada, yada, yada. I'm just taking the characters out for a test drive again. That's my excuse, and I'm sticking to it... Thanks to everyone who has reviewed, you guys are my muses!

HALLIWELL MANSION

Cole looked down at the pictures and listened as Tom went over what he had told the others. At the end he looked up. "I don't know that the artifact is," he said, "Especially as it's way before my time. But this," he gestured at the picture, "I do know. Everyone down below knows him and everyone hopes they never meet him. His name is Tethos."

Leo gaped. "You've got to be wrong, I've met him, he looks nothing like that. thing!"

Cole turned to look at the Whitelighter. "When did you last see him?"

"New York, 1962," was the response. Cole shook his head. "Then you met the old Tethos. Before he changed into that."

"But-" Cole raised a hand. "He changed, Leo. I don't know what happened, but he changed."

Slowly Leo slumped back in his chair. Something inside him seemed to deflate. "Then he finally lost himself," he muttered.

Piper had watched this interplay with an increasing scowl and now she finally broke in. "Do you guys come with subtitles, or could explain what you're talking about? Who is this Titos, or whatever he's called?"

"Tethos," Cole corrected absently. He looked over at Leo. "You'd better start. I'll finish with his career in hell."

Leo nodded slowly and then looked back over at the photo. "His real name - his human name - was Constantine. He was a king of a small Welsh realm in South Wales just before the Norman Invasion of England in 1066. And he was a force for good. Powerful with magic, popular with his people, and instant death on demons. The Church called him 'The Thorn,' as he was always a thorn in the side of the then Source."

"Who hated him," broke in Cole.

"Anyway, he was married to Rhiannon, the daughter of a nobleman, they had a baby son, Constantine's right hand man was his brother Idris, and everything was perfect for him. Until the Source decided that he had interfered with enough of his plans and decided to get rid of him, either by turning or killing him." Leo smiled tightly. "Typical Source.

"He had an ace in the hole though, in the form of Rhiannon. You see, what her father had failed to tell anyone was that his wife had been a demon - so that Rhiannon was half-demon herself."

Paige raised her hand. "How come someone missed that bit out? How can you miss the fact that your wife had a demon mother?"

"Apparently her demon side never manifested itself when she was young. And Rhiannon was good herself, she was a powerful witch who hated demons as much as Constantine." "But the Source did something to her," guessed Tom.

Both Cole and Leo nodded. "He woke her dark side up. He woke the demon inside her," said Cole softly and then winced as Phoebe applied a bandage to the scrape on his arm. Sorry, she mouthed.

Leo leant forwards and he carried on: "He did it slowly, over several months, so as not to warn her. It had finally got to the point where the demon side was awake when Rhiannon was asleep. Even then, it was very weak and. well, what Rhiannon loved, her dark side loved. The Source couldn't do much without forcing her to act, and whatever she was doing to Constantine it seemed that it wasn't having much of an effect.

"Of course the Source got impatient and tried to move too fast. Rhiannon started to notice that something was wrong - she'd go to sleep and then wake up somewhere else, she had terrible nightmares, she felt different, wrong. And Constantine noticed. And drew the wrong conclusions. He thought that she had fallen out of love with him. He was devastated."

Cole raised his hand and Leo nodded. "Whatever his wife did to him when under the control of her demon side, the magic she used did have one effect on him. It woke up his paranoia. The Source was trying to turn him to evil, but it was so slow, as Leo said. But the paranoia and the fear that Rhiannon didn't love him seem to have fed off each other. That's a bad combination." Cole shook his head.

"Especially," said Leo, "When he somehow thought that she was now in love with his brother. One night Rhiannon woke up in their son's nursery and realised she was holding a dagger. She was terrified, she knew that something evil was going on and she ran to Idris's rooms to beg him to help her. She was too afraid of what her husband might do, that he might send her away. I don't know what she was thinking. And then, when she was on her knees crying in front of Idris, who didn't have the faintest idea what was going on, in walked Constantine and everything blew up.

"Constantine thought that his fears were real, he snatched the dagger and... killed his only brother. He was about to kill her as well when the Source made another spectacularly badly timed effort to take over her dark side. Constantine saw something, saw that an evil force was trying to possess her - and then he saw her demon side for the first time."

The room was silent. "What happened?" asked Phoebe in a small voice.

"He realised that there was evil in his wife - and that the Source was involved. So he used a spell to call her demon side to the surface and forced it to tell the truth. Everything, the fact that the Source was trying to influence her, the fact that she didn't know about her demon half, the fact that she loved him deeply... the fact that Idris was innocent. He fell on his knees and broke down in tears, howling for forgiveness.

"The moment she was released from the spell Rhiannon knew everything as well. It must have been shattering. She picked up the dagger and was about to kill herself when Constantine stopped her. He... did something that no one has ever done before or since. He performed a forbidden spell."

Leo drew a deep breath. "He willingly extracted her demon side from the women he loved and absorbed it within himself. He saved her soul by damning his own."

"What?" squeaked Paige.

"The spell's forbidden because it's also incredibly dangerous. If he'd got it wrong, even the smallest part of a word mispronounced, he'd have killed them both. And," said Cole, turning to Phoebe and taking her hands in his, "Don't even think about researching it. No matter how much you want to save me, I'd never agree to transfer any part of my demon side to you. Ever. It's my burden, my penance. My problem."

Phoebe smiled sadly. "What did he do then?" she asked.

"He kissed his wife, kissed their son, announced that he had murdered his brother and then exiled himself. He walked from the castle and never set foot in his kingdom again. Ever." Leo said as he drained the rest of his coffee and then gestured at Cole. "You'd better tell the rest of it."

Cole flexed his arm where Phoebe had put the bandage on it and started to pull his shirt back on. "Well," he said slowly, "Constantine vanished from the world of men. Five years later a demon calling himself Tethos appeared at the Gates of Hell."

"Hell has gates?" quizzed Piper.

"Big ones, very ornate," said Cole grinning. "Not at all practical though, like much of down below. Well, Tethos made quite an impact because he kicked the gates down and then announced that he was here to teach the Source a lesson. The Source sent the usual demon enforcer to teach him a lesson. Tethos killed him. He killed everyone between him and the Source, nothing could stop him. When he reached the Source, he announced that he had once been Constantine, and that he was here to avenge himself. A fairly impressive battle followed, which ended with Tethos nailing the Source to the ceiling of his own throne room with red-hot iron bolts."

"He killed the Source?" broke in Paige. "Way to go! For a demon, that is."

"No," said Cole with an odd smile, "I didn't say that he killed the Source, just that he nailed him to the ceiling."

"That didn't kill him? It would kill me," said Phoebe.

Cole shook his head. "No-one knows just what Tethos did to him. He was left alive but stripped of his powers. He's still alive now."

"Waaittt a minute," Piper protested, "I'm seen pictures of the Source's throne room and there's no dangly evil guy on the ceiling."

Cole shook his head. "That's the new throne room. The old one's in the chambers behind it. The old Source - Malchance his name was, so we'd better call him that to stop any confusion - went mad in 1203, for understandable reasons, and his successor finally had to move rooms because of the insane gibberings."

Piper failed to hide a grin. "So what happened to Tethos?"

"Well, he vanished into the tunnels underneath. It's a labyrinth down there; almost no one knows where they all lead. He disappeared into them. Occasionally someone would see him. As long as they didn't interfere with him, he left them alone."

Her eyes narrowed, Piper leant forwards. "What happened to those that did interfere with him?"

"He killed them. He has a massive amount of power. Remember, he was witch for years, he fought demons, and then he acquired demon powers on top of that. But the problem with the various Sources down the centuries is that they see everything in terms of forces and counter forces, everything boiled down to pieces on a chessboard. Every Source has seen Tethos as a valuable possible assassin. Every Source has sent demons down to meet him, first to recruit him, then to force him to join and finally just to try and get rid of him. Every Source has failed. It's every demon's nightmare to meet Tethos. Including mine," Cole admitted. "The present Source sent a Citalis demon against him in 1946."

"Wow," breathed Leo. He looked at the looks of incomprehension on the faces of the others. "It's a walking tank, almost impossible to kill. Incredibly bad tempered as well. What happened?"

Cole winced. "The Source walked into his throne room the day after and discovered its head on his throne, with a note that said that it was lucky he'd been away when Tethos had called, otherwise he'd have been walking with bow legs from the delivery of the head."

Paige frowned and then winced herself. "But now the Source has put enough of a reward on his head to make people want to try?" she asked.

"A huge amount of money," nodded Cole. "Enough to tempt anyone."

Tom cleared his throat. "And now you say that he's changed?"

"I always thought that he would never give himself to his evil side," said Leo. "Apart from Idris, he's never killed any humans, only demons."

Cole frowned and stood up, looking down at the floor. "Ah... when I was still popular down below," he said, looking uncomfortable, "I was once with the Source when he received a report from one of his spies. It was about 30 years ago, the Source had realised how futile it was to try and kill Tethos by then, and so he set spies on him instead. They started reporting that Tethos had secluded himself in one set of rooms down in the most inaccessible part of the tunnels and had started on a spell. A very long, very powerful, very complex one."

"What kind of spell?" questioned Molly.

"I don't know. No one knows. Tethos left some pretty nasty traps in some of the passageways leading to his chambers. A lot of the Source's spies never came back. I saw what had happened to one of them afterwards - just a head and a hand protruding from a wall. The next time I saw Tethos himself he looked..." Cole gestured at the picture. "Well, like that. I only knew it was him when he spoke. Told me to get out of his way or he'd kill me."

"Sooo..." said Piper, picking up the picture, "We have an all-powerful demon on the loose, apparently with his real dark side on display for the first time in a thousand years, going after an artifact with unknown powers, with the last piece somewhere totally unknown. And that combination has scared the Source enough to post a massive bounty on this demon. Does anyone else not like this picture?"

"I'll ask the Elders about the artifact," offered Leo, picking up one of the photographs of the larger piece and then transforming into a thousand points of blue-white light and vanishing upwards.

Tom looked at the ceiling thoughtfully. "I wish he hadn't done that," he said.

Piper turned to him in surprise. "Why?"

"Because I was about to say that we have a lead on the third piece and that having a Whitelighter about the place could have been quite helpful."

Piper winced. "Leo!"