Siméon or Timeone Riro ʻa Kāinga Rokoroko He Tau[1] (died 1898 or 1899) was the last ‘ariki (king) of Rapa Nui (Easter Island) from 1892 until his death.

Although, his family was from the Miru o Kao branch of the clan with no direct patrilineal relationship with the ancient ariki, but were their tumu (their wives married the men of the royal lineage).

[8][9] Riro's cousin Maria Angata Veri Tahi 'a Pengo Hare Kohou, a Catholic catechist and prophet, organized many of the island's women in his support.

The Chilean government abandoned the settlement in 1892 due to political troubles on the mainland, which was embroiled in civil war, and this prompted the Rapa Nui to reassert their independence.

[12][13] During this period "the Rapanui under Riro Kāinga restored their government in even clearer forms than before the annexation, to the point where it might indeed have qualified as a State, so that its arbitrary second takeover by Chile in 1896 could be considered legally questionable as well.

"[14] Unlike Tekena, Riro reasserted native rule by standing up to foreign residents (such as Charles Higgins) and restored a degree of peace and stability to the island.

Sánchez and his armed guards marched to Hanga Roa to force the strikers back to work; the islanders refused to comply with his order, disarming one of his men in the confrontation.

On the day of their arrival, the Valparaíso provincial intendant offered to forward Riro's case to the government; however, the king insisted on meeting as equals with Chilean president Federico Errázuriz Echaurren.

During the evening, the king was encouraged to drink heavily; the next morning his men were informed that he had been sent to Carlos Van Buren Hospital, where he died of alcohol poisoning.

Riro's relatives unsuccessfully attempted to restore the kingship with Enrique Ika and Moisés Tuʻu Hereveri, despite Sánchez's orders abrogating the institution and forbidding the islanders from choosing a new king.

Personal pretension, supported by Chilean officers who needed a responsible intermediary to deal with the population, might have contributed toward the restoration of power to this fictitious and ephemeral royalty.