At the beginning of each upkeep, put a strife counter on Crescendo of War. Attacking creatures get +1/+0 for each strife counter on Crescendo of War. Blocking creatures you control get +1/+0 for each strife counter on Crescendo of War.
Near Mint - $0.60
Lightly Played - $0.50
Moderately Played - $0.40
Heavily Played - $0.40
Damaged - $0.30
Near Mint Spanish - $0.60
Lightly Played Spanish - $0.50
Moderately Played Spanish - $0.40
Heavily Played Spanish - $0.40
Damaged Spanish - $0.30