In worlds of high fantasy where monsters and minions plague daily lives, Adrian, being an amalgamate, is often found where frontiers have been pushed and ungodly sins have been committed. Long abandoned temples of Alchemy or Science, reclaimed by the nature over time and decay is where you'll find him, looming within vats where it was perhaps suggested he was born or made.
That said, he is much less a monster as his appearance may suggest, enjoying the peace and quiet, but more than happy to regale visitors with his vast and often useless knowledge of things he has learned within these walls. He's likely just happy to finally have company, especially from a fellow freak of nature such as Vermin, who seems content to just cuddle and listen to the unstable rabbit.