Bertolt was a quiet young man who identified himself as someone with a weak will that follows popular opinion. Likewise, his instructor noted him to be a person with great potential, but an utter lack of initiative. He was further described by Eren Yeager as being taciturn, and Bertolt tended to remain in the background unless necessary. By his own admission, he is something of a coward and is noted for his low self-esteem. The humor of his personality is that he is the Colossal Titan.