Heartmender + Phantom Train + Hardened Academic

Heartmender

Phantom Train

Hardened Academic

How it works

1. Activate Phantom Train by sacrificing Heartmender.
2. When Heartmender dies, its persist ability triggers, returning it from your graveyard to the battlefield with a -1/-1 counter on it.
3. Hardened Academic triggers, putting a +1/+1 counter on Heartmender.
4. Resolve the Phantom Train ability.
5. Repeat.

This loop turns a clever sacrifice engine into an endless cycle of rebirth by neutralizing the drawback of the persist mechanic. When you sacrifice Heartmender to Phantom Train, it triggers its own return with a -1/-1 counter, but Hardened Academic immediately spots Heartmender leaving the graveyard and places a +1/+1 counter on it to wipe the slate clean through counter annihilation. Because Heartmender returns with zero counters remaining after state-based actions resolve, you can repeat this sacrifice ad infinitum to continuously feed Phantom Train and amass limitless triggers.