I thought this, too. He was already on thin ice during 1.0, where Nael and the VIIth were withdrawn from Othard and sent to Eorzea, and the XIVth scarcely charged with more than just babysitting van Darnus. He's been under pressure ever since Silvertear--Cid openly roasts him on all this during the cutscene for the "Alive" quest in 1.0.
Then we get to 2.0, and the XIVth are essentially an afterthought in imperial terms, but Gaius' ambition and desperation drive him to accept Ascian interference, taking extreme measures to meet his old goals and restore his dignity and recognised status in the process. And... then Praetorium happens. He makes one last attempt to bring Cid back into the fold, and tries to lure the WoL in as well, which fails miserably. And then explosions!
So what's left for a man
- presumed dead
- from a failure-spiral legion
- who permanently burned his bridges with a young man he considered a son
and
- sank to the level of consorting with giggling Hot Topic couture cultists to get what he wanted
?
Running around picking off Ascians, or at least annoying them out of their host bodies, anonymous and without ties until he dies. Sort of a revenge-resignation hybrid. I'm fascinated.
Also, this might just be my eyes playing tricks on me, but the tatters of Shadowhunter's coat really look like Gaius' old regalia, and that bit of armor he's got fixed with a rope around his arm looks a lot like whatever's left of the gauntlet from that side. I'm too interested.
And also very mad that he's attractive, BAHAHAHA