Lewis is a supporting character in the anime Blood+ who serves as a regular operative of the Red Shield, an organization dedicated to combating chiropterans, the vampire-like creatures central to the series. He is a dark-skinned, bald man with a beard, black eyes, and a slightly chubby build, often seen wearing sunglasses, a tank top, and a jacket. At thirty-one years old and standing 175 centimeters tall, Lewis brings a distinct presence to the group. His background includes time spent as a CIA agent, during which he operated under the alias Sammy, and he maintains useful intelligence connections that aid the Red Shield during missions in the United States.

Personality-wise, Lewis is cheerful and lighthearted, frequently providing comic relief through jokes and playful banter. He enjoys cooking for Saya and the other members of the team, and he takes on the role of a matchmaker, notably trying to encourage a romantic connection between David and Julia. He also enjoys teasing Kai, the younger brother of Saya's adoptive family, adding a dynamic of good-natured ribbing to their interactions. His motivations are rooted in loyalty to the Red Shield and a genuine desire to support Saya in her fight against Diva and the chiropteran threat, though he approaches his duties with a relaxed and humorous demeanor that balances the series heavier moments.

In the story, Lewis is primarily responsible for supplying gadgets and transportation for the Red Shield operatives, ensuring that the team has the logistical support needed for their missions. He frequently accompanies David on operations and fights alongside him in battles against chiropterans, demonstrating his capability as a field operative despite his primarily supportive role. After the destruction of the Red Shield, Lewis continues to live with David and Kai in an orphanage in London, where they actively hunt chiropterans together, and he helps Kai hone his skills as a soldier during the ongoing conflict against Diva and her minions. His key relationships include a close working friendship with David, a mentor-like bond with Kai, and a caring but lighthearted rapport with Saya and the rest of the team. Lewis does not possess supernatural abilities, but his practical skills in logistics, intelligence gathering, and combat support make him a valuable and reliable member of the Red Shield throughout the series.