Blade dancers are even easier to kill than infinite lives infinite grenades infinite health warlocks, if they're in range, headshot snipe, if they're medium range, shoot sometimes with thorn to prevent health regen and shotgun melee them, close range, shotgun melee, and if you die who cares? You have infinite lives remember? Blade dancers have a ridiculously long animation time anyways so if you catch them while they're in using the super you an just shoot them and they can't do anything so take advantage of that and shotgun and then shotgun again while they're rushing you and that should finish them off or just in case finish them off with your sniper-range warlock melee