Theres a major downside: Roaring Moon ex then does 200 damage to itself
It also wont affect nonmana parts of an activation cost, if there are any

Sworn to Darkness Ob Nixilis of the Black Oath | Illustration by Daarken Commander (1) Creature (28) Skirsdag High Priest Nantuko Shade Vampire Hexmage Burnished Hart Flesh Carver Crypt Ghast Disciple of Bolas Evernight Shade Abyssal Persecutor Liliana's Reaver Nekrataal Magus of the Coffers Raving Dead Shriekmaw Bloodgift Demon Demon of Wailing Agonies Drana, Kalastria Bloodchief Ghoulcaller Gisa Gray Merchant of Asphodel Morkrut Banshee Grave Titan Phyrexian Gargantua Pontiff of Blight Reaper from the Abyss Xathrid Demon Butcher of Malakir Overseer of the Damned Pestilence Demon Instant (8) Spoils of Blood Tragic Slip Malicious Affliction Sudden Spoiling Tendrils of Corruption Annihilate Skeletal Scrying Wake the Dead Sorcery (13) Sign in Blood Read the Bones Victimize Syphon Mind Dread Return Mutilate Infernal Offering ther Snap Promise of Power Necromantic Selection Black Sun's Zenith Profane Command Dregs of Sorrow Enchantment (1) Artifact (9) Sol Ring Charcoal Diamond Jet Medallion Mind Stone Swiftfoot Boots Commander's Sphere Unstable Obelisk Worn Powerstone Lashwrithe Land (40) Arcane Lighthouse Barren Moor Bojuka Bog Crypt of Agadeem Everglades Ghost Quarter Myriad Landscape Polluted Mire Swamp x32 Commander, Themes, and Strategy Sworn to Darkness is a deck built around death, dying, and being dead

manga and anime, this TCG has built a huge fan base
Bloodthirsty Conqueror On the surface, the Bloodthirsty Conqueror looks like any other big dumb five drop creature, with the extra synergy of being a vampire with a life gain ability (there are lots of both in MTG Foundations )
(3) Each turn, the first time a monster(s) you control would be destroyed by battle while it is equipped with an Equip Card, it is not destroyed