Is warden queen of pain? I suppose you'd love Kassadin then. I love qop and kassadin)
This week's free champions you could try ezreal (carry) or Leona (support)
I looked up a few more heroes and Kassadin stands out so far. The Queen of Pain is indeed based on the Warden (the base WC3 hero).
Warden
Blink - Teleport, short cool down
Shadow strike - huge single target damage + slow
Fan of Knives - Damage AoE around her
Avatar - Creates a controllable phantom figure that summons invincible minions from dead minions around her.
Dex - Melee
Just loved to blink and annoy enemies with Shadow Strike. Lvl 6 was awesome and could farm by itself.
Witch Doctor:
Hex - Transforms a target into a helpless frog that can't attack nor cast spells and moves at a greatly reduced speed. Can be attacked without breaking, I think it reduced armor as well.
Snake Ward - Can summon up to 3(?) Snake wards that spit at the closest enemies.
Healing Wave - Chain healing.
Vodoo Dance - makes everyone around him, except himself invincible (couldn't care about it)
Int - Ranged
Mainly played with Hex and Snake Wards. Healing wave is helpful as well. Controlled from the back and supported all around him. Hex was on a somewhat short cool down, so could be used to chase heroes, CC them or to get away.