Ninjas need this additional (hidden) passive!!!
the inverse law of ninjas states that the fewer ninjas there are, the stronger the remaining ones must be. as such, i believe that ninjas should have an unlisted passive that portrays this (it should be found under "buffs" when you select them, but not on their character card, because it isnt important): "for every unconscious ninja, all other ninjas increase their attack power by 1%".
depending on unconscious ninjas prevents an ambiguous buff for singular ninjas. this is a small, minimal buff not worth building around and not actually impactful for game balance (+39% damage on the sole 40th ninja left alive after you've lost 39 ninjas is not going to swing the fight. +4% damage on the sole 5th ninja early is not going to swing the fight. etc).
most people wouldnt even notice it because they wont click the buffs tab, but they probably arent ninja appreciators anyway. ninjas are awesome and totally sweet, and i believe that they should have this passive in order to better show their real ultimate power.