Ran into a small problem that could easily ruin this event for unlucky people, facing hidan in this event is veryvery painfull.
Since they all get 300k life (at least for me) and hidan's attack scales of his hp...it's a onceshot for anything (in my case it was death possesion hidan but normal prolly has the same). Thankfully it was only 1 ninja so we could cc/kill him but if you ever run into 3 people using him...

Not sure what can be done here, but it could run into some issues (I assume water main strength attack will have the same problem, but more manageable)