Sliver Swarmlord

Eminence — Whenever a player cast a Sliver
spell, if Sliver Swarmlord is in the command
zone or on the battlefield, that player create a 1/1
colorless Sliver creature token.
Sliver spell cost {1} less to cast
"Each sliver brought with it more slivers, and soon
they overran the city's defenders."