Is Rhys, the Evermore legal in Standard, Modern, and Commander?

Rhys, the Evermore is legal in: Standard, Modern, Pioneer, Legacy, Vintage, Commander, Historic.

Rhys, the Evermore

Q: What type of card is Rhys, the Evermore?

Rhys, the Evermore is a Legendary Creature — Elf Warrior. Its oracle text reads: "Flash When Rhys enters, another target creature you control gains persist until end of turn. (When it 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.) {W}, {T}: Remove any number of counters from target creature you control. Activate only as a sorcery."

Legendary Creature — Elf Warrior

$0.32 ↗20 similarCommander, Modern

Flash

When Rhys enters, another target creature you control gains persist until end of turn. (When it 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.)

, : Remove any number of counters from target creature you control. Activate only as a sorcery.