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 - $1.70
Lightly Played - $1.40
Moderately Played - $1.20
Heavily Played - $1.10
Damaged - $0.90
Near Mint Spanish - $1.70
Lightly Played Spanish - $1.40
Moderately Played Spanish - $1.20
Heavily Played Spanish - $1.10
Damaged Spanish - $0.90