Finally feel comfortable to share some of my halo headcanons, certainly after rereading Empty Throne again. Primarily about Grey Team. (Also, because I don't have any finished art due to workloads but shhh)
Grey Team headcanons
Grey Team is in a polyamorous relationship, even if they aren't totally certain of the right terms.
Adriana-111 is the big spoon of the relationship and fully enjoys holding Jai-006 or Michael-120 close to her. In a way, it makes her feel like she could keep them safe. Certainly, in the aftermath of Empty Throne.
Jai can and will listen to Adriana and Michael discuss things like weapons, technology and explosives. In a similar vein, Adriana and Michael have spent hours discussing explosives.
Grey Team has a photo of them and Mendez that isn't standing at ease, or any military formalities. It's more like a family photo. They also occasionally kept in touch at the start of the war, usually as a "Hey we aren't dead yet lol" message.
Grey Team also keeps in contact with Melody as much as they're able to. Adriana is quietly concerned about how Melody is handling things after the events of Envoy.
If they encounter UNSC forces further back behind enemy lines that weren't planned, they usually get the other parties to agree that they never saw them there. “We never heard of Spartans here.” “And you’ll keep it that way, Sergeant.”
Their love language that isn't focused on their individual interests is food. This usually results in Adriana trying to sneak good food back to Jai and Michael when she's doing undercover work. They also stole food in training together. Mendez likely knew this but allowed it to happen so long as they weren't caught to further their teams training regarding stealth and item retrieval.
If one of the team vouches for you, that's usually good enough for the other two. Exceptions can be ones like Delgado from Cole protocol, usually to external circumstances.
Grey Team suffers nightmares about Glyke. They've found some small bit of comfort in sleeping next to each other or holding each other when they sleep.
Adriana will take little knick knacks of technology back to Michael for him to mess around with when she returns from undercover work.
Jai is actually good with makeup and often helps Adriana with putting it on if she needs to wear it.
During the Spartan-II's week 'off' at Emerald Cove, Adriana and Michael buried Jai in the sand when he slept. He has not lived this down.
Adriana's nickname is Adri, however she's only called that by the other two in private when they aren't on any active missions.
Other headcanons
August-099 has imposter syndrome about leading Omega Team. This persists even despite Robert-025 and Leon-011's assurances when it rears its head quite badly.
Fred-104 has basically adopted Ferret Team. Best he can anyways.
Leon-011 doesn't actually talk much despite the game dialogue. He tends to keep quiet as a personal preference. Robert and August have learned to interpret his signals to them and forms of communication. He's always been quiet, even during training.
Douglas-042 would be a bubble tea shop kinda guy. Rock up in full armor because he has some leave but wasn't allowed to take the armor off for whatever reason and ask for suggestions from whoever is working.
Red Team as the start of their time on the Spirit of Fire were confused with each other. Mainly Alice-130 and Douglas-042. People forgot to look at the numbers.
Robert gave Alice her nickname of "Hurricane Alice." He also gave her "Crazy Cici" but that never caught on quite as well. It remains an inside joke now.
Douglas' shoulder hurts in colder temperatures after Atriox crushed it.
The Spartan-IIs are at minimum bilingual in English and Hungarian. However, if they came from a colony world that didn't primarily speak either language, they're multilingual.
