...Ah. One of those. Good luck with that. Such large-scale conflicts have a way of greatly changing your life and routine, and not always for the better.

[His home still shows scars from its previous conflict, and that's with only one world involved.]

It could also be dual-typed with both Steel and Grass, but that's just asking for a Fire-type attack. Hardly the sort of protection and solidity you'd expect from a door.