Bertolt Hoover is a fictional character from the manga and anime "Shingeki no Kyojin" (Attack on Titan). He is a soldier of the Survey Corps and is part of the group of shifting titans. Throughout the series, it is revealed that Bertolt is actually the Colossal Titan, one of the most powerful enemies humans face in history. His role in the plot is crucial and his character develops in complex ways throughout the series.