Whenever a player casts a noncreature spell, they lose 2 life.
Mai is a mono-black aggressive punisher commander: deploy a low, creature-heavy curve, attack with a first-striking body, and let the table bleed itself out every time anyone casts a noncreature spell. You lean on creatures (and equipment/auras minimally) so the symmetry hurts opponents far more than you, supplementing the chip damage with edicts, drain effects, and Voltron pressure on Mai.
Punishes the spell-heavy decks that dominate cEDH and high-power tables—removal, ramp rocks, and combo pieces all cost life
First strike makes Mai a strong attacker and a deterrent blocker for a 2-mana commander
Symmetry is easily turned one-sided since your own deck can be built nearly all creatures
Cheap to recast and slots into fast mono-black aggro that closes games before opponents stabilize
Mono-black means weak interaction with artifacts and enchantments and no access to counterspells
The punishment ability is symmetrical—your own noncreature spells, ramp, and removal cost you life too
Easily removed for a 2-mana creature, and decks ignore the life loss if they're winning fast
Low life-total plans can be raced; cards like Sanguine Bond combos or lifegain hate hose you
Creature-light wraths punish you, so a one-card sweeper like this lets you reset boards without flooding noncreature spells.
Tighten the curve toward creatures and creature-based interaction (edicts, sacrifice removal) so the symmetrical life loss stays one-sided, and add fast mana like Dark Ritual and a few signature rituals despite the self-tax. Prioritize tutors (Demonic Tutor, Vampiric Tutor) to assemble the Sanguine Bond/Vito drain combo, and round out with efficient recursion (Reanimate, Phyrexian Reclamation) to grind. At the top end, lean into a focused drain-combo finish rather than pure aggro to compete at higher power.