Is Krovikan Whispers legal in Standard, Modern, and Commander?

Krovikan Whispers is legal in: Modern, Legacy, Vintage, Commander.

Krovikan Whispers

Q: What type of card is Krovikan Whispers?

Krovikan Whispers is an Enchantment — Aura. Its oracle text reads: "Enchant creature Cumulative upkeep {U} or {B} (At the beginning of your upkeep, put an age counter on this permanent, then sacrifice it unless you pay its upkeep cost for each age counter on it.) You control enchanted creature. When this Aura is put into a graveyard from the battlefield, you lose 2 life for each age counter on it."

Enchantment — Aura

Enchant creature

Cumulative upkeep or (At the beginning of your upkeep, put an age counter on this permanent, then sacrifice it unless you pay its upkeep cost for each age counter on it.)