Euphorbia kuwaleana is a shrub species growing 0.2–0.9 meters tall, characterized by its reddish-brown young bark and older, dark gray, and glaucous bark. The stems are erect and many-branched, with young branch ends that are villous, becoming glabrate with age, except at the pilose nodes, and flowering branches measuring 1–2 mm in diameter. The leaves are simple, opposite, and distichous, with ovate to rarely orbicular blades measuring 11–25 mm in length and 8–15 mm in width. The leaf apex is rounded and retuse, with a cordate, oblique base. The lower surfaces of the leaves are glabrous or villous along the midvein and pilose at the basal margin, often appearing glaucous. The leaf margins are entire, with 0.5–1 mm long petioles and pilose. Stipules are rounded–triangular, measuring 0.5–1 mm long, and are villous, occasionally erose. The flowers are in a cyathia, solitary in the leaf axils or rarely terminal, with peduncles 0–0.5 mm long and glabrous. The involucre is campanulate, measuring 1–1.5 mm in height and 1.5–2 mm in width, and is glabrous to villous beneath the glands, which are usually glabrous and number four. The flowers are unisexual and highly reduced, with solitary pistillate flowers on a gynophore and staminate flowers grouped in 5 cymules, each comprising one to several flowers. Both calyx and corolla are absent, with the male flowers reduced to a single stamen. The fruit is a glabrous capsule, with recurved gynophores exserted approximately 1.2 mm from the involucre and pubescent. It occurs on arid volcanic cliffs and is found at approximately 250 meters.