The Balance of Dichotomy
The In-betweener is the concept of 'concepts'. He walks between every concept. Thus he can never be touched by any concepts but he can touch and affect the concepts. This is also why he is unaffected by the soul gem and even reality itself.
In fact, even magic cannot touch or affect him.
Neither can the power cosmic.
He can never fully die or never fully live.
He is the separator of laws such as actualities and dichotomies. He exists in a realm that is between fact and fantasy, reality and illusion and time and space. It is said that In-betweener's realm is "countless dimensions" away from 616 reality.
Turns the 616 reality into pure madness. Says he can affect all reality and all fantasy.
It takes all of The Ancient One's skill just to see the In-betweener in his realm.
Just as a show of power, ragdolls Strange through different timelines and reality. Strange is so helpless that he momentarily becomes insane just from getting ragdolled like this.
Casually summons Death and forces her to kill some Elders of the universe.
A half-split down version of In-betweener manifests and imbues himself in EVERY aspect of S.H.I.E.L.D.
His other half avatar can reach out and pluck random possibilities across "all infinite timelines and universes" and control them.
His two split avatars clashing causes the universe to be ripped apart.
He knows everything that conspires even in a timeline that has been reset.
