Tom Ksaver

Possessing an inquisitive mind, Ksaver was always curious about how the Titans came to be and mentioned to a young Zeke Yeager that he joined the Titan Biology Research Society primarily because of his curiosity. Usually seen with a smile on his face, Ksaver was an easy-going man with a slight care-free attitude; he was also compassionate and comforted Zeke after the boy turned in his parents to the Marleyan authorities. Underneath Ksaver's friendly nature, he also harbored feelings of self-loathing, along with a desire to kill himself as a means to atone for the part he unknowingly played in the deaths of his family. He also seemed to care little about the ideals of the Warrior Unit by calling it stupid to shorten one's lifespan just to invade other countries.

Human Form
Ksaver had short dark hair and a round face. He wore the traditional apparel of a Warrior and a red armband, showing that he was an Eldian and an honorary Marleyan. Ksaver also wore glasses that Zeke Yeager would later wear as an adult.

Ksaver's main occupation in Marley was being a Titan researcher, implying he was experienced in Titan physiology and had a degree of knowledge about Titans.