Keyword: Amass

Up to one target creature gets -2/-2 until end of turn. Amass 2. (Put two +1/+1 counters on an Army you control. If you don’t control one, create a 0/0 black Zombie Army creature token first.)

When Vizier of the Scorpion enters the battlefield, amass 1. (Put a +1/+1 counter on an Army you control. If you don’t control one, create a 0/0 black Zombie Army creature token first.)
Zombie tokens you control have deathtouch.

At the beginning of your upkeep, you lose 1 life and amass 1. (Put a +1/+1 counter on an Army you control. If you don’t control one, create a 0/0 black Zombie Army creature token first.)
Whenever a Zombie token you control with power 6 or greater attacks, it gains lifelink until end of turn.

Flying
When Aven Eternal enters the battlefield, amass 1. (Put a +1/+1 counter on an Army you control. If you don’t control one, create a 0/0 black Zombie Army creature token first.)

When Lazotep Reaver enters the battlefield, amass 1. (Put a +1/+1 counter on an Army you control. If you don’t control one, create a 0/0 black Zombie Army creature token first.)

First strike
When Grim Initiate dies, amass 1. (Put a +1/+1 counter on an Army you control. If you don’t control one, create a 0/0 black Zombie Army creature token first.)

When Gleaming Overseer enters the battlefield, amass 1. (Put a +1/+1 counter on an Army you control. If you don’t control one, create a 0/0 black Zombie Army creature token first.)
Zombie tokens you control have hexproof and menace.

Counter target spell unless its controller pays .
Amass 2. (Put two +1/+1 counters on an Army you control. If you don’t control one, create a 0/0 black Zombie Army creature token first.)

Amass 2, then the Army you amassed deals damage equal to its power to each non-Army creature. (To amass 2, put two +1/+1 counters on an Army you control. If you don’t control one, create a 0/0 black Zombie Army creature token first.)

When Herald of the Dreadhorde dies, amass 2. (Put two +1/+1 counters on an Army you control. If you don’t control one, create a 0/0 black Zombie Army creature token first.)

Return target nonland permanent to its owner’s hand.
Amass 1. (Put a +1/+1 counter on an Army you control. If you don’t control one, create a 0/0 black Zombie Army creature token first.)

Creatures you control have menace.
−2: Amass 2. (Put two +1/+1 counters on an Army you control. If you don’t control one, create a 0/0 black Zombie Army creature token first.)