The eye of Sauron

Towers you cast cost {b}{r} less to cast.
Demons you control get +1/+1
Whenever a demon enters the battlefield under your control, the eye of sauron deals 2 damage to any target.
Whenever a tower enters the battlefield under your control, the eye of sauron deals 4 damage to any target.
"Concealed within his fortress, the lord of Mordor sees all.
his gaze pierces cloud, shadow, earth, and flesh."-Saruman, lord of Isengard