<Snipped quote by The Grey Dust>
I concur, I like the concept. There are, however, some balance issues, like magus permanence. He could potentially maintain multiple magus (magi?), and I feel that gives him an advantage over other characters if he can simply accumulate abilities. Perhaps he could "forget"?
Furthermore, it feels a little tricky for him to be "the glitch in the system" and fool the universe. That makes him a slightly different from everyone else and allows him to disable other characters's abilities, which is a little... haunting, to say the least. Makes me feel like the rest of the world when the US dropped the atom bomb—a gap in power. It seems like he can essentially win a one-on-one fight using a practiced mental link by disabling the other opponent's abilities.
Of course, not to say I might be reading you wrong or that he's 100% unbalanced. I just need it clarified for me, so I can be assured that he's not able to singlehandedly beat everyone. Just concerned, that's all. But it might be okay with Jenno.
He can only keep one at a time, regardless of duration. The psychic link over a long period of time is created and lingers, but he can still only maintain one connection active at a given time. Thus no, he cannot "collect" the powers of others and store them as his own indefinitely. I apologize if it was unclear, it was a minor tagline in the abilities which explained he only retains one at a time and copying another magnus replaces the one he currently has regardless of duration.
And the idea is that yes, he can potential shut down others, this also means he cannot simply copy another character who is a powerful mage at their consent for a week's time and become essentially another mage all together. Hence to prevent this from happening, there must be some backdraw to letting him copy your magick (e.g. to essential produce another mage capable of doing the exact same things which could generate interesting recursive combos) which would be the eventual stealing of one's abilities. Thus we cannot have two omnipowerful magi running around between the two of them for indefinite periods of time should they enter a partnership to rule the world(s).
And of course, one does not go on a one-on-one duel with Ibyxx for obvious reasons, or at least not without being prepared to face yourself. It is better to bring friends along, but you should be able to beat them too as he may be inclined to borrow their powers too.