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 - $1.500
Lightly Played - $1.200
Moderately Played - $1.000
Heavily Played - $900
Damaged - $800
Near Mint Spanish - $1.500
Lightly Played Spanish - $1.200
Moderately Played Spanish - $1.000
Heavily Played Spanish - $900
Damaged Spanish - $800