As one of the guys said above go +hp -armor and put him at +hp tactics spot. He has scaling armor passive and they will focus him from round one. His mystery scales more of attack rather than ninjutsu.

I would personally go +hp -res and put him on +hp spot on tactics , since he has scaling defense passive and he is immune to debuffs and ignition and poison won't work on him that's why I would go -res . Just a personal opinion though. I wouldn't go -att since his mystery and standard stack of attack.

I did lol.