Is Necropolis Fiend legal in Standard, Modern, and Commander?

Necropolis Fiend is legal in: Modern, Pioneer, Legacy, Vintage, Commander, Historic.

Necropolis Fiend

Q: What type of card is Necropolis Fiend?

Necropolis Fiend is a Creature — Demon. Its oracle text reads: "Delve (Each card you exile from your graveyard while casting this spell pays for {1}.) Flying {X}, {T}, Exile X cards from your graveyard: Target creature gets -X/-X until end of turn."