Four booster packs from battling Go to Imanaku in the Fighting Club after talking to a girl at the Fire Club
It transforms if everyone has less than 10 life - hard with a 40-life starting format like Commander - but becomes a 1/4 flying deathtouch to play keep away from bigger things and then when it swings you gain a trio of life

Cadira, Caller of the Small + Doubling Season + Trostani, Selesnya's Voice Infinite ETB, infinite lifegain, infinite lifegain triggers, infinite LTB, infinite sacrifice triggers, infinite death triggers, infinite creature tokens, infinite storm count Archfiend of Depravity + Archfiend of Despair Infinite sacrifice triggers for opponent's creatures over turns, Infinite amplified life loss for opponents over turns, Opponents lose the game Archfiend of Depravity + Archfiend of Despair (Denial Lock) Recurring board wipe for opponents, recurring life loss for opponents, severe board control, opponents cannot gain life Knight-Errant of Eos's Deep Search & Board Fill Put up to four creature cards from the top of your library into your hand, enabling a powerful board presence or assembling a non-infinite combo
That ensures Damn is always what the player needs it to be when drawn, either spot removal when the caster has a decent board or a board wipe when the caster is far behind