Infinite +1/+1 counters on a creatureInfinite combat damageInfinite combat phasesInfinite death triggersInfinite creature ETBInfinite lifegainInfinite lifegain triggersInfinite creature LTBInfinite mana creatures you control can produceInfinite creature sacrifice triggersInfinite untap of creatures you control
How it works
Declare Carmen and the creature with Breath of Fury attached as attackers.
Carmen's second ability triggers, returning a creature card with haste from your graveyard to the battlefield.
Deal combat damage using the creature that has Breath of Fury attached.
Breath of Fury triggers, causing you to sacrifice the creature it is attached to, then attach Breath of Fury to another creature with haste, then causing you to untap all creatures you control and to get an additional combat phase after this one.
Carmen's first ability triggers, putting a +1/+1 counter on it and causing you to gain 1 life.
Repeat.
This loop turns Breath of Fury into an endless succession of attacks by tethering it to your aggressive board state. When the enchanted creature connects, it sacrifices itself to restart the process, which triggers Carmen, Cruel Skymarcher to grow larger and consistently resurrect a hasty accomplice from your graveyard. Because Carmen keeps scaling up in power with every sacrifice, her reanimation net widens each turn, ensuring you always have a fresh vessel ready to carry Breath of Fury into the next combat phase.