Gabriel's one of the newer angels on Asa's council, along with Raphael, Michael, and Tabris. Known mainly for being one of the no-nonsense, 'Shoot first, ask later' angels on the council (Not to mention, the one with massive amounts of gun porn), his tactics have changed severely since being sealed. Now, it's more akin to 'Shoot first to incapacitate, then ask questions when they come to'.
A fellow member of Abaddon's former council, and for centuries, the only one who's been able to call Gabriel off of doing anything. He doesn't approve of Gabriel's habits: drinking, smoking, cussing, etc., and in return, Gabriel doesn't approve of his nagging. In Gabriel's little headspace, Michael's the mother of the group since he's the most nuturing and supportive of their group, as well as one of the oldest ones.
Gabriel and Raphael rarely see eye to eye on things. Where Gabriel is poor at most forms of magic, especially healing, Raphael can't do much more than such. However, the two of them were also paired in the past, combining Gabriel's offensive with Raphael's healing.
Tabris was often partnered with Gabriel for minor missons, and as thus, the two know a good amount about each other.
As one might expect, these two either get along or they clash. It's usually the former, but this mun suspects that if they were to both be in a bad mood and near each other. . . oh dear.
Of all the veteran angels, Gabriel interacts with Kamiu the most. This is likely due to him spending so much time in the yellow room at the RainBar. However, very little of this has been shown ICly, other than Kamiu knowing the exact point where he should be cutting Gabe off (Generally viewed as somewhere in the middle of his singing), and Gabe knowing that, after a bit, his liquor turns to water but he's too drunk to care. They also are technically each other's counterparts.
In short? Alter-Tabris who also can't stand meat. Which means he may act more daddy-ish if needed towards Peter.
Considering Gabriel is the guardian to two of Cecilia's children, one would think they'd know each other rather well. Unfortunately, this isn't quite the case.
He thinks Kyle's a dumbass, but push comes to shove? He's there for him. Well, when he's not busy racking up points for the kid.
He likes Kali. . . when she's not being all Disney-happy.
Mentioning Gabriel's past wards to him is one way to send him into a depression, furthering it into a blind rage and finally, a cold and ruthless soldier who seeks only to cause pain in the smallest hopes that it would help ease his own.
The first set of twins that Gabriel was ever tasked to watch.
Gabe kind of. . . started to snap when he died.
Any others have yet to been mentioned or seen.