At the beginning of combat on your turn, another target Elemental you control gains myriad until end of turn. (Whenever it attacks, for each opponent other than defending player, you may create a token copy that's tapped and attacking that player or a planeswalker they control. Exile the tokens at end of combat.)
Mass of Mysteries is a 5-color Elemental tribal beatdown commander that turns one of your Elementals into a multi-pronged threat each combat via myriad. You ramp into a board of impactful Elementals, then grant myriad to a creature with a powerful attack trigger or huge body so token copies hit every opponent at once, multiplying value and damage.
Five-color identity gives access to the best ramp, removal, and Elementals in the format.
Myriad multiplies attack/ETB triggers across all opponents for explosive value swings.
Commander has evasive-adjacent combat keywords (first strike, vigilance, trample) and stays back on defense.
Elemental tribal is deep, with strong payoffs and lords across all colors.
Myriad tokens are exiled at end of combat, so the value is fleeting without ETB or attack triggers.
Five-color mana base is expensive and prone to color screw without strong fixing.
Relies on having a second Elemental to target each turn; light boards stall the engine.
Token copies are vulnerable to board wipes and combat tricks before triggers resolve.
Powerful Elemental whose ETB ramps for each myriad copy, accelerating your mana hugely.
Prioritize a smoother 5-color mana base with fetchlands, duals, Triomes, and ramp like Cultivate, Farseek, and mana rocks to reliably cast everything. Add more high-impact Elementals with strong ETB or attack triggers (Risen Reef, Cryptic Trilobite, Avenger of Zendikar) so each myriad activation generates maximum value, plus anthem and overrun effects (Craterhoof Behemoth) to convert wide boards into kills. Round out with interaction and protection to keep your engine creatures alive through wraths.
Legendary Creature — Elemental
