I'm looking for games, where you can level either a minion, pet, or weapon - indirectly from your character.
I don't really mind what style of game it is.

A few games that come to mind are: Ultima Online, (taming - leveling pets), Disgaea(item world, and weapons). As you can see the genre doesn't really matter.

I really enjoyed the idea of taking a very weak item, or pet - and making it incredibly strong(I remember a chicken I had in a private UO server that could stand toe-to-toe with a dragon for example, or taking one of the starting weapons in disgaea, and with proper setup - making it stat capped, or near it.) These kind of things are really enjoyable.

Does anybody know of similar systems in other games? I don't mind if it's MMO, RPG, Action, Adventure, or whatever. thanks for any responses!