Serpent ascension + blade spin = dead ofc with buffs (blade spin is 0% crit ability so alone having +5 crit is a nice dmg boost, maybe paired with a good combo including crit addons somewhere (helps for shadow stomp (0 crit ability) too, idk where they are on ninja skills) . RBF ninjas usually add a few more abilities and maybe do other combos, including the shackles rabam. Also im a Kunoichi so pretty squishy, just as many other classes. Sometimes serpent ascension or blade spin alone take 70% of my hp. Not sure about the ninjas gear but it happens frequently. They usually don't take more than 2-3s to kill someone when they do a quick combo. And that's the true strength of ninja. PS: I'm not a ninja so don't ask me about his dmg combos or anything. Shadow stomp is a hard hitter too.