Which Dos Pilas ruler was a brother of Tikal king Nuun Ujol Chaak?

The Dos Pilas ruler who was a brother of Tikal king Nuun Ujol Chaak was Bʼalaj Chan Kʼawiil.

Bʼalaj Chan Kʼawiil founded the Dos Pilas dynasty in the Petexbatún region, but he claimed descent from Tikal’s royal house. His relationship with Nuun Ujol Chaak illustrates how Maya royal families could divide into rival political branches while preserving a shared dynastic identity.

The brothers became enemies during the conflict between Tikal and Dos Pilas. In 672, Nuun Ujol Chaak attacked Dos Pilas and forced Bʼalaj Chan Kʼawiil into exile. Bʼalaj later returned with support from Calakmul, Tikal’s great rival, and recovered his position after the balance of power shifted.

The other choices belong to different contexts. Yuknoom Chʼeen II was a powerful ruler of Calakmul, Kʼinich Yax Kʼukʼ Moʼ founded Copán’s ruling dynasty, and Yikʼin Chan Kʼawiil was a later king of Tikal. The kinship is sometimes rendered as brother or half-brother, but Bʼalaj Chan Kʼawiil is the canonical answer.