Seneschal was an ancient being who once caused the Doctor's TARDIS to bring the Seventh Doctor into his presence. He told the Doctor he was of a race responsible for seeding the entire universe with life. He also said he was personally responsible for human evolution, and that he spent two hundred million years just watching seaweed develop. By most definitions, therefore, he was a god.
The Doctor, however, didn't consider him a deity, but an "intergalactic busybody" who shouldn't have been "meddl[ing] in the primordial soup of innocent planets". This assessment predictably incensed Seneschal, who chased the Doctor out of his presence.
Unbeknownst to the Doctor, the ancient being had stolen the tiniest amount of the Doctor's skin, hoping he could use the constituent DNA to rebuild the gene pool of the Time Lords. (COMIC: The Sentinel)
Behind the scenes
In the real world, seneschal is a medieval French word for a kind of steward or majordomo for a noble house.