This card, despite what you might expect, is actually a Green instant that costs one mana
While that balance has shifted over the years (along with plenty of other archetype-defining cards that have come and gone), Mana Drain continues to find ways to make control viable, despite how intense of competition it faces
Here are the decks on EDHREC.com that run him - 16,627 decks
I will then walk through each criterion as it applies to each rarity

Aerie Ouphes Affectionate Indrik Agatha's Champion Aggressive Instinct Ambuscade Ana Battlemage Ancient Animus Animist's Might Archdruid's Charm Arena Assert Perfection Atzocan Archer Bartz and Boko Betrayal at the Vault Bite Down Bite Down on Crime Blizzard Brawl Bridgeworks Battle Burrog Barrage Bushwhack Cartouche of Strength Chainweb Aracnir Chelonian Tackle Chocobo Kick Clear Shot Colossal Collision Contest of Claws Contested Cliffs Cosmic Hunger Dalek Intensive Care Dawnsire, Sunstar Dreadnought Delif's Cone Devouring Tendrils Diplomatic Relations Duel for Dominance Durkwood Tracker Epic Confrontation Extinguisher Battleship Farrel's Mantle Felling Blow Feral Encounter Finishing Move Gargantuan Gorilla Garruk Relentless Garruk, Savage Herald Giggling Skitterspike Gruesome Slaughter Halana, Kessig Ranger Hard-Hitting Question Horrific Assault Huatli's Final Strike Hulk's Thunderclap Hunt the Weak Hunter's Bow Hunter's Edge Hunter's Mark Hunter's Talent Infectious Bite It's Clobberin' Time

Thats just a good time for everyone, isnt it