The return of nostalgic Leaders as brand-new Leaders suggests that Bandai may use OP-17 to refresh existing archetypes or reintroduce older strategies in a modern form
A key reason to add black is for Callous Sell-Sword, which can sacrifice Heartfire Hero for the win

Four-Color Control (7.5% of the Winner's Metagame) 4 Tablet of Discovery 4 Inevitable Defeat 4 Jeskai Revelation 4 Great Hall of the Biblioplex 4 Stock Up 3 Consult the Star Charts 3 Steam Vents 3 Sacred Foundry 2 Shattered Sanctum 2 Flashback 2 Mistrise Village 2 Sear 2 Stormcarved Coast 2 Day of Judgment 2 No More Lies 2 Hallowed Fountain 2 Firebending Lesson 2 Riverpyre Verge 1 Plains 1 Cori Mountain Monastery 1 Lightning Helix 1 Multiversal Passage 1 North Wind Avatar 1 Godless Shrine 1 Sundown Pass 1 Sunbillow Verge 1 Gloomlake Verge 1 Abrade 1 Three Steps Ahead 2 Flashfreeze 2 Emeritus of Ideation 2 Strategic Betrayal 1 Outrageous Robbery 1 Disdainful Stroke 1 Petrified Hamlet 1 Day of Judgment 1 Ancient Vendetta 1 Negate 1 Pest Control 1 Pyroclasm 1 Riverchurn Monument Four-Color Control seeks to dictate the pace of the game through a carefully balanced mix of countermagic, removal, sweepers, and card-draw spells
VIOLET EXPANSION PACK RULER OF THE BLACK FLAME - SV3 - (BOX) Co
If you ever find yourself lucky enough to obtain one of these, be sure not ever to give it up
If you don't control an Army, create a 0/0 black Zombie Army creature token first.) Card Details Set War of the Spark (WAR) Rarity rare Colors BR Artist Victor Adame Minguez Collector # 226