My Forces Are Innumerable — ruling 1

To pay the cost of this scheme’s second ability, your opponents need to sacrifice two creatures total. Those creatures may be controlled by different teammates.

My Forces Are Innumerable — ruling 2

In a Supervillain Rumble game, this scheme’s last ability triggers at the beginning of each opponent’s end step. Only that player may sacrifice creatures.

My Forces Are Innumerable : règles, fonctionnement et interactions (MTG)

My Forces Are Innumerable is one of those cards players keep asking about. Here is, in plain words, what its official text says, the rulings published by Wizards of the Coast, and the combos players actually run.

Official card text

(An ongoing scheme remains face up until it's abandoned.) At the beginning of your end step, create a 3/3 black Horror creature token. At the beginning of your opponents' end step, they may sacrifice two creatures of their choice. If they do, abandon this scheme.

How it works : My Forces Are Innumerable

Original English text — Wizards of the Coast / Scryfall

#1June 13, 2017· Wizards of the Coast
To pay the cost of this scheme’s second ability, your opponents need to sacrifice two creatures total. Those creatures may be controlled by different teammates.
No other card is named in this ruling.
#2June 13, 2017· Wizards of the Coast
In a Supervillain Rumble game, this scheme’s last ability triggers at the beginning of each opponent’s end step. Only that player may sacrifice creatures.
No other card is named in this ruling.