He disapproved of using torture as a means of interrogation not only because it was ineffective, but because he had personal experience with it as well: he had scars from insurrectionist torture running from his wrists to his elbows, and he also had scars around his neck. The Prowler Corps rescued him from torture, and thus he became very loyal to them.
In 2535, Watanabe proposed the UNSC Midsummer Night's mission to go to Charybdis IX and track and eliminate the source of smuggled Covenant weaponry. He was, for the most part, disliked by the Midsummer Night's crew due to the fact that he was quiet and secretive, spending most of the journey to Charybdis IX in his personal quarters. He had read the Carver Findings and agreed with them: Watanabe believed that the colonies were a powder keg due to their innumerable cultures and religions, and that a constant war, such as the Insurrection, was inevitable. He often compared the Insurrection to the Rain Forest Wars.
After Petty Officer Jeffries' Pelican was shot down over the Scyllion Warehouse District, Watanabe helped Lieutenant Jacob Keyes snap out of his guilt trance and back into reality. Watanabe was killed by insurrectionist Jason Kincaide while defending the crew's extraction point alongside Keyes and ONI agent Captain Corinthia Hansen. His death was avenged by Keyes, who killed Kincade in retaliation.
Personality and traits
Watanabe was known for his cold approach toward individuals and for his single-minded focus on his mission. Although observant and detail-oriented like most ONI personnel, he did not pay much attention to personal details of those he served alongside; Keyes noted this fact when Watanabe carelessly miscalled Jeffries "Jefferson" after the pilot was killed. Those treated by him in such a way still felt pangs of sadness when Watanabe died, however. Despite his being an ONI operative, he did not believe in torture as many members of ONI did due to his own experiences of being tortured and stated that if he was overly loyal to the ONI Prowler Corps, it was because they had rescued him from a living hell. Instead, Watanabe believed in using more subtle and ingenious methods of interrogation that were physically harmless to the subject. Watanabe did not trust easily due to his experiences and status as an ONI operative. However, he proved himself to be a good judge of character, determining that Lieutenant Jacob Keyes was someone he could trust implicitly just from his actions on Finnegan's Wake. Watanabe also felt that most of the bridge crew were similarly trustworthy, but hesitated to bring them along because he knew that they didn't like him and wasn't sure how that would play out in a moment when a split-second decision needed to be made.
List of appearances