Oompo belongs to the Boomps, a band of shapeshifting goblins dwelling in Slumberland. Alongside Oompa, Oomp, Oompe, and Oompy, the Boomps wield innate resistance to the Nightmare King’s corrupting magic. Crossing paths with Nemo in Nightmare Land after his allies are seized by the Nightmare King’s minions, the group aids him in his perilous quest. Upon reuniting with a long-separated member of their clan, Oompo delivers a pivotal letter from King Morpheus to Nemo, revealing the royal scepter’s activation incantation. This crucial act empowers Nemo to challenge and ultimately overthrow the Nightmare King. During the climactic clash, the Boomps fight alongside Nemo and Icarus, aiding Morpheus’s liberation and the restoration of Nightmare Land. In later tales, the Boomps reemerge to bolster Nemo and his comrades with steadfast encouragement during a clash between opposing factions. Their roles remain tied to these documented events, with no expanded lore on Oompo’s personal history or further adventures disclosed.