Is Demonlord of Ashmouth legal in Standard, Modern, and Commander?

Demonlord of Ashmouth is legal in: Modern, Legacy, Vintage, Commander.

Demonlord of Ashmouth

Q: What type of card is Demonlord of Ashmouth?

Demonlord of Ashmouth is a Creature — Demon. Its oracle text reads: "Flying When this creature enters, exile it unless you sacrifice another creature. Undying (When this creature dies, if it had no +1/+1 counters on it, return it to the battlefield under its owner's control with a +1/+1 counter on it.) Power/Toughness: 5/4"

Creature — Demon

Flying

When this creature enters, exile it unless you sacrifice another creature.

Undying (When this creature dies, if it had no +1/+1 counters on it, return it to the battlefield under its owner's control with a +1/+1 counter on it.)

Power/Toughness: 5/4

Set Avacyn Restored

Rarity Rare

Mana Value 4

Artist Lucas Graciano

Collector # 96

Scryfall