Whenever you cast an instant or sorcery spell from your hand, you may cast up to one target card of the other type from your graveyard. If a spell cast from your graveyard this way would be put into your graveyard, exile it instead.
Choose a Background (You can have a Background as a second commander.)
Cast instants and sorceries from hand to flashback the opposite type from your graveyard, chaining cheap cantrips and counterspells into card advantage and tempo. You sculpt a stocked graveyard early, then use Gale to double-dip on spells while building toward a mill, draw-engine, or storm-style finish. Pair with a Background to give the deck a closing dimension.
Free recast of one graveyard spell per cast doubles your effective spell count and card advantage
Cheap commander (3 MV) that fits any spellslinger curve and rebuys quickly
Background slot lets you tailor the deck (ramp, recursion, voltron) to your meta
Mono-blue gives best-in-class card selection, counters, and protection