Whenever an opponent casts a spell, put a +1/+1 counter on Ishai.
Partner (You can have two commanders if both have partner.)
Ishai grows rapidly off opponents' spellcasting, becoming a huge evasive threat that you turn into a Voltron win with auras and equipment. As a Partner commander, you pair her with a second legend to add a strategy or color while suiting up Ishai to swing for lethal commander damage. You protect her, give her double strike and trample, and close fast before the table can answer.
Free, repeatable scaling in multiplayer—Ishai often becomes a 6/6+ flyer by turn 4-5 with no investment
Flying evasion makes commander-damage kills reliable
Partner flexibility lets you splash a third color or a whole second gameplan
Cheap to recast at 4 mana, resilient to bounce/grow-back plans
Removal-dependent: targeted removal, edicts, or -X/-X resets the counter investment
No built-in protection or evasion beyond flying
Stalls against decks that don't cast many spells (or play around her on your turn)
Aura/equipment-heavy builds risk card disadvantage to two-for-ones
Extra combat plus double strike turns a grown Ishai into a one-attack kill.
Pick a Partner that defines the deck—Rograkh for cheap Boros Voltron, Tymna for card draw, Bruse Tarl for double-strike alpha strikes—then add protection (Lightning Greaves, Whispersilk Cloak, Robe of the Archmagi) and evasion/double strike (Aqueous Form, Battle Mastery). Lean on cheap card-advantage enchantments (Sram, Mesa Enchantress) and tutors (Steelshaper's Gift, Open the Armory) to assemble your kill consistently. Tighten the mana base with fast lands and rocks so you suit up and swing before removal catches up.