Tillis has a weaselly, rat-like appearance that makes him naturally forgettable - exactly what he wants. He's thin and angular with sharp, narrow features, pale to sickly yellow skin, and pale, watery grey eyes that dart around nervously. His sparse, unkempt brown hair and slightly crooked teeth add to his generally shifty appearance. Despite his unsavory looks, he maintains the basic grooming standards of a League Navy supply officer, making him unremarkable enough to avoid scrutiny while maintaining access to military logistics and resources.
A Sooni operative working under Commander Janus in an anti-Focus cell, Tillis serves as a supply officer aboard the LSS Athena while pursuing his own agenda. He uses his true Sooni name "Tillis" as a surname while adopting various generic first names as obvious pseudonyms for different identities. His "official" League identity is Robert Tillis, though he gives different equally generic first names to different groups he works with - never revealing his true Sooni name or using a consistent first name.
Unlike the ideologically driven members of Janus's cell, Tillis appears motivated primarily by loose allegiances and personal gain rather than any strong anti-Focus convictions. He represents the mercenary element within the anti-Focus movement - useful for operations requiring flexible morality and multiple identities.
During the New Athens terrorist incident, Tillis played a crucial role in Commander Janus's manipulation by executing Captain [Rodney Klein][] after Klein and Itonia Ross had wounded each other. Tillis was positioned to ensure Klein's death regardless of how the confrontation played out. After completing this task, he chose to help the mortally wounded Ross escape, showing a pragmatic understanding of changing circumstances and the value of maintaining some personal standards even while serving ruthless masters.
Tillis serves under Janus in both his official capacity as a League supply officer and his covert role in the anti-Focus Sooni cell. Their relationship appears purely professional, based on mutual utility rather than shared ideology.
After executing Captain Klein as planned, Tillis chose to help the dying Nox escape from the destroyed shipyard, honoring his word to get her to safety before abandoning her. This interaction revealed both his pragmatic nature and his adherence to certain personal codes of conduct, even after completing his primary mission.