Omega (Doctor Who)

Omega — born as Peylix, also known as "the Engineer" and Omegon, and worshipped as Ohm — was a great intergalactic engineer and co-founder of Time Lord society, but centuries of loneliness and isolation bent his mind so that he threatened the entire universe. He was the only person ever to live within the anti-matter universe, which he subsequently ruled over while he used his will to enable him to construct a landscape, with the permission of the anti-matter creature. However, his existence in this realm robbed him of his body and left only his conscious will intact, a realisation that twisted him into murderous insanity aimed towards the Time Lords, whom he blamed for abandoning him to his fate.