The Golden Runesmith / Arcanist Karsus

I think I remebmer being told about him... If he's still around, it does not bode well.
— Rebis
He kept pressuring me to say yes to something... But it felt wrong.
— Baal
Do not. Trust that... Fucking thing.
— Fate
  The Golden Runesmith, or Arcanist Karsus, the The Momentary God, or the Unmaker, is an individual who has provided precious little. Fate claims that back in the suuuper old days the dude tried to convince them to just say yes to merging his world with theirs. He would just jump around from overseer to overseer of realities in order to find someone to say yes to. The guy had a bag of runestones on his side, but had a amazing comprehension of all things magical.   Arcanist Karsus claimed to the original seven that he attempted to usurp a energy being, and paid the cost for it. But in it, he had expanded his conciousness to everything in existence, and became similar to the 'Philospher Stone' of the modern day. That which contains everything in existence, except for his single universal system, where his world now lays in stasis. He claims he'd be able to raise endless wonders for the original seven who went on to become the dimensional seals, but the aspect of divinity, Fate, was the only one to turn him down thinking it seemed 'too good to be true at such a crucial time.'   However; despite his aid, he isn't afraid to play both sides to find and locate things. All Major Runic Children confirm that he is their creator, and subsequent abandoner when they don't work in his favor. He is the one who truly aided Monad in the creation of Pallor; the manipulation of Baal on the planet vemeter, and so on and so forth.   He is seen giving up extremely easy and moving onto the next thing, not truly engaging in open combat. He has been ran into by the Onism party, and when he was manhandled he was extremely angry to the point where he uncharacteristically 'snapped'. However, Fate claims, that he did provide some pretty pivotal information which helped them move along.   He is constantly on the move, with hideouts everywhere and anywhere laying hidden. He has claimed to have the ability to percieve the 'unseen world', and can make magical creatures appear infront of others, and is the only individual in existence known to be able to craft 13th level spells.   There are no recorded instances where individuals have agreed with him, but the Rebis warns this; letting loose all of those generation 5 C'tans into existence would be an amazing benefit, but it would provide completely unforseen consequences, as they truly do not know the extent of any of them. Especially seeing as Karsus seemingly has a high amount of hidden motives, considering his infamous and most brutal line that he despises divines, and openly tells the story of him slaying a C'tan, something that was thought impossible. Keeping him away from the Rebis at all cost is a high priority.
Arcanist Karsus psychological profile is that of a folly of excessive arrogance and ambition, with endless hubris. His general vibe is uncomfortability when around him, and his hostility to divinities; in specific- Fate- is the only reason why the original seven seals did not agree to him.
Children