Marty Tohn is Shirotsugh Lhadatt's closest friend within the Royal Space Force. He acts as a grounded counterpoint to Shirotsugh's philosophical turmoil and Riquinni's religious idealism, operating within the military structure. Marty actively participates in the Space Force's efforts to launch the first human into orbit, persisting despite public skepticism and government manipulation.

Following Shirotsugh's disillusionment and his assault of Riquinni, Marty encounters his friend in despair as Shirotsugh questions if he might be the villain of his own story. Marty responds with a pragmatic worldview centered on human interdependence, asserting that people fundamentally exist because they serve purposes for one another. This perspective directly contrasts Riquinni's teachings on inherent human sinfulness.

Marty remains involved as tensions escalate before the rocket launch. He is present during the assassination attempt on Shirotsugh by an agent of the rival Republic. His role within the final launch sequence and the broader military conflict between the Kingdom of Honnêamise and the Republic is not detailed. He appears solely within the original film.