Is Stalwart Successor legal in Standard, Modern, and Commander?

Stalwart Successor is legal in: Standard, Modern, Pioneer, Legacy, Vintage, Commander, Historic.

Stalwart Successor

Q: What type of card is Stalwart Successor?

Stalwart Successor is a Creature — Human Warrior. Its oracle text reads: "Menace (This creature can't be blocked except by two or more creatures.) Whenever one or more counters are put on a creature you control, if it's the first time counters have been put on that creature this turn, put a +1/+1 counter on that creature. Power/Toughness: 3/2"

Creature — Human Warrior

Menace (This creature can't be blocked except by two or more creatures.)

Whenever one or more counters are put on a creature you control, if it's the first time counters have been put on that creature this turn, put a +1/+1 counter on that creature.

Power/Toughness: 3/2

Set Tarkir: Dragonstorm

Rarity Uncommon

Mana Value 3

Artist Bastien L. Deharme

Collector # 227

Scryfall