Sir Henry Curtis (Zulu name: Incubu, which means "Elephant") was the constant companion and fellow traveler of Allan Quatermain.
Sir Henry first became acquainted with Quatermain when he left from England to Natal province, South Africa to request help in search of his brother, George Curtis. Although unwilling at first, Quatermain is eventually persuaded to help lead him along with Commander John Good of the Royal Navy to the Heart of Kukuanaland, where George is expected to have disappeared looking for King Solomon's Mines.
Sir Henry is especially noted for his enormous size and stature, his muscular physique, and his long, blonde, locks, no doubt inherited from his Danish forebears.
Sir Henry is, especially in Kukuanaland, noted for his bravery in battle, such as when he lead the Greys, the elite regiment in the Kukuana army, against the evil king Twala in an unevenly matched battle, with Twala having the advantage, or even when he slays the king himself in hand-to-hand combat. He is so highly decorated, that any feat of strength afterward in Kukuanaland is known as Incubu's Blow.
In 1886 Allan having persuaded Sir Henry Curtis, Captain John Good and Umslopogaas to accompany him they set out from the coast of east Africa into the territory of the Masai and while staying with a Scottish missionary are attacked by a group of these tribesmen whom they overcome with heroism. There follows a voyage along an underground river to a lake in the kingdom of Zu-Vendis, a warlike white race entirely isolated ruled jointly by two sisters, Nyleptha and Sorais.
Both fall passionately in love with Curtis and this together with the rejection by Sorais of the nobleman Nasta results in a civil war between them (Sorais and Nasta's forces against those of Nyleptha, Curtis and Quatermain).
After a battle Queen Nyleptha is victorious but then threatened by the treachery of the priests who plan to murder her in the palace. Umslopogaas and one loyal warrior manage to save her from Nasta and the chief priest Agon. Umslopogaas hurled himself against Nasta as he lifted his axe against the Queen.
Sorais, defeated and jealous, takes her own life: Nyleptha and Curtis become King and Queen.