- "Santiago is an exemplary soldier and one of the most courageous men I've ever met. But even with his outstanding record, I can't recommend his promotion to corporal. His loyalty to Fenix may well exceed his loyalty to the COG. Even if it doesn't, then his decision to testify for Fenix must call his judgment into question, However... even if I have refuse his promotion, I'll state privately that this is a man I can only admire for his refusal to abandon a friend, knowing what it would cost him"
- — Lieutenant Colonel James Amstin, assessing Private Dominic Santiago shortly after Marcus Fenix's court martial
The Trial of Marcus Fenix was a controversial court-martial of the Pendulum Wars hero Sgt.Marcus Fenix. He was court-martialed under the grounds of failing to obey orders, punching out his CO and helping to cause the fall of Ephyra during the Battle of Ephyra. Chief of the COG Defense Staff Colonel Victor Hoffman led the trial against Marcus, with an NCOG captain overseeing the trial, while Cpl.Dominic Santiago testified in Marcus' defense. Marcus was accused of abandoning his post and men to save his father Adam Fenix from attacking Locust, and abandoning his men and taking the Hammer of Dawn front targeting optic with him, leaving many of his fellow Gears to die and allowing the Locust to penetrate the Jacinto Plateau and capture the southern part of Ephyra, giving the Locust a minor decisive victory. Marcus was found guilty and was originally sentenced to death by a firing squad, but the sentence was reduced to 40 years in Jacinto Maximum Security Prison. He would only serve four years when Dom broke him out during the Lightmass Offensive. The fallout of the trial would lead to Dom Santiago losing any future promotion opportunities and to Hoffman losing respect for Marcus.