Is Warlock Class legal in Standard, Modern, and Commander?

Warlock Class is legal in: Modern, Pioneer, Legacy, Vintage, Commander, Historic.

Warlock Class

Q: What type of card is Warlock Class?

Warlock Class is an Enchantment — Class. Its oracle text reads: "(Gain the next level as a sorcery to add its ability.) At the beginning of your end step, if a creature died this turn, each opponent loses 1 life. {1}{B}: Level 2 When this Class becomes level 2, look at the top three cards of your library. Put one of them into your hand and the rest into your graveyard. {6}{B}: Level 3 At the beginning of your end step, each opponent loses life equal to the life they lost this turn. (Damage causes loss of life.)"