Is Fallen Askari legal in Standard, Modern, and Commander?

Fallen Askari is legal in: Legacy, Vintage, Commander, Pauper.

Fallen Askari

Q: What type of card is Fallen Askari?

Fallen Askari is a Creature — Human Knight. Its oracle text reads: "Flanking (Whenever a creature without flanking blocks this creature, the blocking creature gets -1/-1 until end of turn.)Fallen Askari can't block."

Creature — Human Knight

Flanking (Whenever a creature without flanking blocks this creature, the blocking creature gets -1/-1 until end of turn.)<br>Fallen Askari can't block.

Set Visions

Rarity Common

Artist Adrian Smith