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 - $1.300
Lightly Played - $1.000
Moderately Played - $900
Heavily Played - $800
Damaged - $700
Near Mint Spanish - $1.300
Lightly Played Spanish - $1.000
Moderately Played Spanish - $900
Heavily Played Spanish - $800
Damaged Spanish - $700