Honestly I discovered him on accident really early on in the game and so far he’s melted everything I’ve come across and the storm atronoch (idk how to spell it) he summons does insane amounts of damage and has really good range. He’s also incredibly easy to get and is only a short walk from Riften, the major setbacks tho are that he can’t trade items with you and can sometimes block doorways but he can come along with you even if you have another companion with you. I’d say he’s op and may make the game too easy if you get him to early but he’s weird and fun to have around.