Violet dance EP is not tanky by any means. It has no antistun besides purify spell, which not all clerics even have (not to mention it has a funny way of only working when you don't need it). If you can't adequately lock a violet dance ep who doesn't have puri spell as an aps class, you also kinda deserve to die lol. If you debuff your enemy, or run a gof weapon; you won't take as much damage from the soulburn. When I fight metal mages on my bm, I tend to finish them with dragon long sword. Random high gof crits + less soulburn dmg = a good time.