Each instant and sorcery card in your graveyard has flashback. The flashback cost is equal to that card's mana cost.
Lier turns your graveyard into a second hand by giving every instant and sorcery flashback, so you durdle through cantrips and removal early, then recast your whole yard for double the value once Lier hits the battlefield. You win by chaining draw and burn spells into a lethal storm/recursion turn, often locking opponents out of interaction since their counters do nothing against you. Treat the early game as setting up card advantage and protecting Lier, then go off in one big flashback turn.
Spells can't be countered shuts off a huge swath of blue interaction
Doubles the value of every instant/sorcery via flashback, giving relentless card advantage
Mono-blue gives access to the best counters, cantrips, and tutors when Lier isn't out
Excellent at grinding out attrition matchups thanks to recursion engines
Lier is fragile and a high-priority kill-on-sight target
Flashback cards exile after use, so the engine can run dry without recursion
Mono-blue struggles to interact with resolved permanents and lacks ramp
Vulnerable to graveyard hate which can blank the entire strategy
Needs Lier on board to function, making it commander-dependent
Legendary Creature — Human Wizard
