For example, if two creatures you control with lifelink deal combat damage at the same time, Drogskol Reaver's last ability will trigger twice
Shimmer Dragon EDH | Commander | Stephen Johnson Commander (1) 1 Shimmer Dragon Creatures (30) 1 Broodstar 1 Shimmer Dragon 1 Treasure Mage 1 Vedalken Archmage 1 Vedalken Humiliator 1 Alloy Myr 1 Brass Squire 1 Burnished Hart 1 Etherium Sculptor 1 Foundry Inspector 1 Hovermyr 1 Karn, Silver Golem 1 Kuldotha Forgemaster 1 Metalwork Colossus 1 Myr Battlesphere 1 Myr Enforcer 1 Myr Galvanizer 1 Myr Propagator 1 Myr Retriever 1 Myr Welder 1 Palladium Myr 1 Padeem, Consul of Innovation 1 Phyrexian Metamorph 1 Pilgrim's Eye 1 Platinum Angel 1 Shimmer Myr 1 Silver Myr 1 Solemn Simulacrum 1 Urza, Lord High Artificer 1 Walking Atlas Instants (8) 1 Aetherize 1 Aetherspouts 1 Counterspell 1 Flusterstorm 1 Rapid Hybridization 1 Stoic Rebuttal 1 Swan Song 1 Whir of Invention Sorceries (1) 1 Fabricate Enchantments (2) 1 Frogify 1 Rhystic Study Artifacts (24) 1 Arcane Signet 1 Blinkmoth Urn 1 Crawlspace 1 Darksteel Forge 1 Darksteel Plate 1 Extraplanar Lens 1 Fellwar Stone 1 Fireshrieker 1 Genesis Chamber 1 Mind Stone 1 Myr Incubator 1 Myr Turbine 1 Ring of Three Wishes 1 Sol Ring 1 Spectral Searchlight 1 Sword of the Animist 1 Tormod's Crypt 1 Trailblazer's Boots 1 Unwinding Clock 1 Whispersilk Cloak 1 Blackblade Reforged 1 Hammer of Nazahn 1 Shadowspear 1 The Immortal Sun If you wanted to run this list as a regular Commander deck, you might swap out Shimmer Dragon for Padeem, Consul of Innovation
While the power level doesnt seem overly high, duplicating a spell can be game-swinging, and being able to always have that ability was deemed too strong for Commander
Credits of Pokmon Gold and Silver on MobyGames
Expect that third one to be lurking around somewhere close by
Black has specific cards it wants to play for specific power levels and win conditions
