AS you may notice the Demon Lord is OP within close range, Riktor is also OP unless you got some stealthy rogue

The Hero is like mostly just a normal swordsman, oh and the elf is just a magic user...

I was lazy but in general the DemonLord is fast even without magic, the Strongest Demon is similar to Sakura or Tsunade from Naruto just less OP his not levelling mountains or anything though depending on how you look at it if we let him go on a rampage he could take out a mountain given enough time...

The Hero is balanced and the elf is also balanced, the demonlord is the weakest when not using his magic, while his servants can all fight without magic for the most part...

Either way the assassin's are stronger than these four characters, but are a bit on the only take out specific targets and after that they just leave... I think the demonlord the only one who can counter the assassin's due to the assassin's actually having a weakness to his magic anyways hope they not too OP for you to handle