Some NPCs are seemly particularly nasty, being dangerous even to teams of myths sometimes...

What ones are the strongest?

Mergula is the strongest?
Balrog?

The dude in Calia castle :P Nazgul is a mean bastard aswell but he can be negated.

Krom?

That the one, proper bastard :P

Re Albi castle rat.
I wonder how bad he was?

Turkeysaurus! Nah, maybe not? Or? He was pretty mean!

DOesent count since he's an event boss :P

I recall a Nazgulfight long time ago.
Some became poisoned and that poison was really nasty and it had a long long effect time.
"exa poisons"
This command or a similar one, not sure exactly, worked fine for some reason and you could count the number of poisons which often at Nazgul or Deamonlord in Emerald could count up to plenty (15 was not rare in the Emerald mine).
Those days CON gave a lot more hitpoints so fights lasted longer than today (maybe todays size of players even out) but having many poisons dropped health badly.
So death was lurking, unless...
Unless you took the boat to Re Albi (Cadu) and went to the wishing well where you can drop coins in the well.
But "drop poison in well" also worked fine. :)

LOL
Why now we dint have such wells? Maybe Sparkle well works like that? :-)

There are easier ways to get rid of poisons... :)