Szarel, Genesis Shepherd + Animation Module + Sword of the Meek + Ashnod's Altar + Phantom Train

Szarel, Genesis Shepherd

Animation Module

Sword of the Meek

Ashnod's Altar

Phantom Train

How it works

1. Activate Phantom Train by sacrificing Sword of the Meek.
2. When you sacrifice Sword of the Meek, Szarel triggers, putting a number of +1/+1 counters on another creature you control.
3. Animation Module triggers, causing you to pay 1 to create a 1/1 Servo artifact creature token.
4. When the Servo enters the battlefield, Sword of the Meek triggers, returning itself from your graveyard to the battlefield attached to the Servo.
5. Resolve the Phantom Train ability.
6. Activate Ashnod's Altar by sacrificing the Servo, adding CC.
7. Repeat.

This loop turns a clever sacrifice engine into a self-sustaining manufacturing line, fueled by Ashnod's Altar providing more than enough colorless mana to keep the gears turning. Phantom Train starts the process by consuming Sword of the Meek, which in turn triggers Szarel, Genesis Shepherd to pump up your board with +1/+1 counters. Those counters immediately awaken Animation Module to pay for a fresh 1/1 Servo token, whose entrance prompts Sword of the Meek to leap straight back out of the graveyard and onto the battlefield, ready to be fed to the Train all over again.