Refer to the passage below and then answer the question afterwards in the same language as the passage:

Passage: The story follows the adventures of Garde pilot Nagate Tanikaze, who lived in the underground layer of Sidonia since birth and was raised by his grandfather. Never having met anyone else, he trains himself in an old Guardian pilot simulator every day, eventually mastering it. After his grandfather's death, he emerges to the surface and is selected as a Guardian pilot, just as Sidonia is once again threatened by the Gauna.

Question: What is he selected as after the passing of his grandfather?
Guardian pilot