Varimathras by Derpifier

Enemies you attack have Legion's Bidding applied to them. Legion's Bidding engulfs the enemy in green flames and if the effect lasts more than 15 seconds on an enemy, a Fel Demon is spawned at their location. This is applied every 15 seconds Legion's Bidding is placed on an enemy. Legion's Bidding lasts 5 seconds.

Shoot a fireball that damages nearby enemies on impact. 130 (+4%) damage to main target, 65 (+4%) to nearby enemies.

60 mana - 8 seconds

Incapacitate an enemy for 3 seconds.

70 mana - 17 seconds

Your basic attacks heal you for 100% of damage done for 5 seconds.

50 mana - 15 seconds

Deal 1000 (+4%) damage over time to an enemy, if killed they spawn a Doomguard for 13 seconds.

100 mana - 100 seconds

Turn nearby minions into zombies, which have twice those minions' stats.

90 mana - 80 seconds

Like Illidan's R1 mount.