Golden Frieza uses this attack at the start of his battle with Super Saiyan BlueGoku, after hitting Goku into a mountain Frieza fires his Emperor's Death Beam at the godly Saiyan.
When Frieza is recruited by Goku to participate in the Tournament of Power, they are recepted by assassins, and Frieza kills all of them with his improved Emperor's Death Beam.
Video games appearances
Emperor's Death Beam was named in Dragon Ball Xenoverse, where it appears as Golden Form Frieza's Ultimate Skill. It can also be obtained by the Future Warrior In DLC pack 3 in New Parallel Quest: "Frieza's Siege Against the Earth!". The amount of beams fired depends on the amount of ki the user has. It is a part of the Resurrection ‘F’ Pack DLC.
The attack also appears in Zenkai Battle under the name Death Counter. In this appearance it is used as a counter rather than an ultimate attack.