|Birth name||Sergio D'Onofrio|
|Affiliations||Pan Pacific Defense Corps|
|Jaegers Piloted||Brawler Yukon|
|Appears in||Pacific Rim: Tales From Year Zero|
Like Adam Casey, Sergio was among the test pilots assigned to them by the PPDC. When Caitlin Lightcap goes through the procedure of checking Sergio’s physical and mental health status, she spots high dopamine levels in his brain activity and asks if the Lieutenant is obsessive-compulsive. Her question sparks his concern, but further evaluation reveals Sergio has a crush on her. Regardless, Sergio maintains professionalism with Dr. Lightcap despite his feelings. Just a month after Casey’s death, Sergio is assigned to pilot the Brawler Yukon.
He manages to get the Brawler to walk before he’s overwhelmed by the neural load. Lightcap’s quick thinking with the Pons in the control tower observing his demo, allows her to successfully connect with his mind. Her efforts manage to save not only Sergio, but the Jaeger Program itself. From thereon out, Sergio and Lightcap trained and worked together during Drift sessions. Their relationship strengthened by the bond created by the Drift, the two fall in love with each other.
Lightcap was hesitant to commit, still involved with Jasper Schoenfeld. Instead of forcing the issue, Sergio reminds her that the world, not Schoenfeld, needs her and asks what she wants out of the situation. Once Lightcap ends her relationship with Schoenfeld, the two pursue theirs. On April 23, 2015, the Kaiju Karloff attacks Vancouver. Sergio and Lightcap are sent by out by the PPDC to face the monster in the Brawler Yukon despite its status as prototype Jaeger. The two are able to destroy the creature with the Jaeger, powered by the strength of their bond.