Before joining Red Shield, David was the sole survivor of a chiropteran attack on his special forces squad. His father was also a member of Red Shield and was one of Saya's victims in the Vietnam incident. It is implied that he, along with Joel, are the only members that are descended from a line of Red Shield operatives. He is aware of Saya's past life and wishes to use her in the struggle against the chiroptera. David's red crystal item is a cross.
David tends to be straight-faced and serious, with a cold personality. However, he also assumes an unofficial guardianship of Kai and Riku, and would be instrumental in helping Kai come to terms with what Saya is and with Riku's conversion to a chevalier. He seems to take a particular interest in helping Kai grow up to be a strong man who can support Saya and Riku as their brother, despite their unusual natures.