Activate Shilgengar by sacrificing Marionette Master.
When Marionette Master dies, its persist ability triggers, returning it from your graveyard to the battlefield with a -1/-1 counter on it.
When Marionette Master enters, its fabricate ability triggers, putting a +1/+1 counter on it.
Resolve the Shilgengar ability.
Repeat.
This clever loop turns Shilgengar, Sire of Famine into a relentless engine by leveraging the persistent resurrection granted by Isilu, Carrier of Twilight (the back face of Eirdu, Carrier of Dawn). When you sacrifice Marionette Master to Shilgengar's ability, its persist ability brings it back with a -1/+1 counter configuration neutralized immediately by its own fabricate trigger, keeping its power intact and generating Blood tokens in the process. Meanwhile, Marionette Master's triggered ability ensures that every artifact sacrificed or discarded along the way bleeds your opponents out.