Whenever Olivia attacks, return target creature card from your graveyard to the battlefield tapped and attacking. It gains "When you don't control a legendary Vampire, exile this creature."
Cheat big creatures into play for free every combat by attacking with Olivia, building an army of reanimated threats that swing immediately. Fill your graveyard early with discard, dig, and self-mill, then attack on turn six to start reanimating bombs that close the game fast.
Reanimates a creature attacking and tapped every single combat at no mana cost
Has haste, so she can attack and reanimate the turn she lands
Flying makes her hard to block and reliable at triggering
Recurs your best dead creatures repeatedly for explosive, snowballing boards
Reanimated creatures are exiled if Olivia or another legendary Vampire dies or leaves play
Heavily commander-dependent; without her on the battlefield the engine stalls
Vulnerable to removal, especially during the declare-attackers window
Six mana and must survive to combat before generating value
Reanimated and attacking, it grants an extra combat to trigger Olivia again for another reanimation.
Add fast mana and ramp (Sol Ring, Arcane Signet, Rakdos Signet) to land Olivia ahead of curve, plus protection like Lightning Greaves to shield her at the attack step. Tighten the graveyard package with Entomb, Reanimate, and Animate Dead for redundancy, and lean into multiple legendary Vampires (Anje, Edgar enemies aside) so reanimated bombs stick around even if Olivia is removed.