Heroic Self-Deprecation: He's utterly convinced for most of the comic that he's not a good spy (which isn't entirely true - his only failing as a spy is his refusal to kill people, he's still pretty good at the subterfuge elements that come with the job), and that BLU Scout would probably lose interest in him at some point.
Messy Hair: It gets worse as time goes on due to stress.
Socially Awkward Hero: Actually manages to stay calm in the face of danger (unless it involves fire), but still manages to act like a complete dork the rest of the time.
Scars Are Forever: Has permanent burn scars on his right side on his shoulder, arm, etc.
Tan Lines: As time goes on, his mask causes the area around his eyes and mouth to tan a lot more than the rest of his face.
Technical Pacifist: He'll shoot you if it saves a life, but if possible, he won't make it a kill shot. He's afraid that he will like killing. He later is forced to kill Khalil, the red pyro, and he accidentally kills Blue Medic when the medic tried to kill Jeremy for being useless.
Attention Whore: At one point he lies and says that he did all the work in a fight and while Jordi was cowering. He leaves out the part where Jordi took back his gun right from under Gabriele's nose and shot Red Engineer.
The Smart Guy: Figures out the solution about how to use the hidden cameras to develop an early warning system to a train's arrival.
Miguel, Rojo, Spy
"I'm zhe hero in zhis s'ory."
Morphic Resonance: Though it hasn't been commented on within the comic itself, his disguises are usually given away to the readers by his almost luminescent green eyes.
Out-Gambitted: He didn't know it, but his plan to disable the Blus was doomed to fail. He assumed that the Blu team would be humane enough to treat their disabled and keep them alive. Blu medic was killing Rojo's victims who couldn't be healed or didn't want to be healed.
Well-Intentioned Extremist: He at least thinks he's this - he seems to be under the delusion that if he can disable the members of the BLU team (as the team members are only replaced when one of them dies), then they'd have to surrender and RED can win the war, ending the conflict. Because of this mindset, he's done some pretty awful things to the BLU team, whilst thinking that he's "the hero of this story" and that anyone going against him is a traitor.
What the Hell Is That Accent?: He's from Basque Country. Basque is not a part of any known language family tree, making his accent very unique. He also speaks Spanish and, given the region, may also speak some French.
Foil: For Rojo. He's calm, logical, and team-oriented, whereas Rojo is... not.
Psychopathic Manchild: He is more psycopathic than Blue Pyro. He delights in the burn wounds Bleu has and, realizing Bleu is as flammable as anyone, he quickly runs to get lighter fluid for a barbeque. The title of that page outrights says he's insane.