Mandatory effects (強制効果 Kyōsei Kōka), also known as Compulsory effects, are effects that must activate and are not Optional. When two or more effects trigger at the same time, mandatory effects resolve at the beginning of the Chain, and Optional effects resolve at the end. Mandatory effects are identified in cards by the word "must" or the phrase "this is not optional". Monsters with mandatory effects usually lack the phrase "you can" in the card text. Certain cards like "Caius the Shadow Monarch" and "Man-Eater Bug" may seem powerful, but they can unintentionally work against the player when the opponent's field is clear.