Mandatory effect

Mandatory effects (強（きょう）制（せい）効（こう）果（か） Kyōsei Kōka), also known as Compulsory effects, are effects that must activate. When two or more effects trigger at the same time, mandatory effects activates at the beginning of the Chain, and Optional effects activates later.

Mandatory effects lack the phrase "You can" in the card text (In Japanese, Mandatory Effect is indicated by the text 発（はつ）動（どう）する Hatsudō suru, which translates to "Activate"), or it is written (This is not Optional) . 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.

Example