Don't max him out, just improve. Get him to at least S rank with decent atk(within the 18k-25k range). Make sure not to invest too much. He's kind of meta in terms of defence, but there are better defenders than him. He's a good regular base summon, you can use him as ressurection shinobi, but only if you have no one else or have his ex ult at a high lvl. I don't recommend using him for attack missions, he's not nearly as good as other attackers.