Sat atop a pillar, The Underlord will bombard the player from its pedestal for the duration of the battle. The Arena consists of 3 stone columns immediately accessible to the player, with a large central platform that initially holds the player, which offers two bridges that branch off to the other columns. These hold the Towers of Light, in which the player must combat Light Guardians, and by defeating them, deal damage to the Underlord.
Upon beating a Light Guardian, the column supporting the Tower of Light will give out, and the player must flee to the middle island, and defeat the second Light Guardian.
Upon beating both Light Guardians and escaping to the central column, a bridge of light will form, giving access The Underlord's column. You must then climb up it, as it attacks you, and find its soul. The battle with its soul is similar to the Light Guardians, and the fight is described on their page.
"Underlord, Fallen Deity, (by Ploomutoo)" plays during the battle.