Tim Sullivan was an agent of A.R.G.U.S., kidnapped by Shadowspire in retaliation for his involvement on operations run on them.
Tim Sullivan graduated from Starling University with a Bachelor of Science in Chemistry. Afterwards, he became involved in A.R.G.U.S., serving as their agent and liaison to the Army Special Forces from 2009 to 2011.
In 2013, Sullivan worked with fellow agents Alan Chang and John Le in crippling Shadowspire, an organization of war profiteers posing as a Special Forces unit.
In January 2016, Sullivan and Le went missing two days before Alan Chang was kidnapped, tortured and killed by Shadowspire, indicating they met the same fate.
Genius-level intellect: Sullivan had a confirmed IQ of 170.
Expert chemist: Having a BS in Chemistry, Sullivan was an adept chemist.
Computer engineering: Sullivan was reportedly very good at technology and advanced computer engineering.
According to his A.R.G.U.S. profile, Sullivan's hobbies were hiking and reading comic books.
The photograph of Sullivan is actually that of writer Emilio Aldrich appearing in a cameo.
Interestingly enough, he had Emilio had co-written this episode with fellow writer Brian Ford Sullivan, who shares a surname with Aldrich's character but appears himself as a fellow A.R.G.U.S. member John Le.