When Garna enters, return to your hand all creature cards in your graveyard that were put there from anywhere this turn.
Other creatures you control have haste.
Garna turns your sacrifice outlets and combat trades into card advantage by recurring everything that died this turn when she enters, while also handing your whole team haste. You play a Rakdos aristocrats/sacrifice game—dump bodies, sacrifice them for value, then flash in or recast Garna to reload your hand and immediately swing or sacrifice again.
Recurs all creatures that died this turn at once, generating massive card advantage with mass sacrifice or wraths
Grants the whole board haste, making reanimation and token swarms attack the turn they arrive
Flash lets her ambush block or dodge sorcery-speed removal and reset value on your end step
Excellent payoff in aristocrats shells that already want creatures dying
Only returns creatures that died THIS turn—prior graveyard fodder is left behind
Returns to hand, not the battlefield, so you must re-pay mana to deploy them
Five-mana commander that does nothing the turn she dies unless you have sacrifice synergies online
Vulnerable to graveyard hate that exiles creatures before her trigger resolves
BR lacks strong noncombat protection and ramp compared to other color pairs