I love Thragg and Kregg, I have some wild headcanons regarding them🥹
(Spoilers for the comics) I find the fact that Thragg became the most frustrated by Kregg's "betrayal" kinda shows that Thragg and Kregg, at least on SOME level, were close. I don't think there could ever be romantic relationship between them(I don't hate the ship, I understand people would ship it, I just have my own reasonings on why I find their relationship more platonic/again, NOT SAYING THEY COULDN'T BE A THING/) I think the infamous Viltrumite "the weak are killed, affection is weakness so prepare to be taken out you little affectionate fucker" thingy forces their society to invent new ways of being affectionate with one another, because yeah even they need it. And Kregg and Thragg are affectionate with one another, the professional way, humans would never even interpret them as respectful, hell what do you mean their professionalism is a sign of fucking 'affection', but let me put y'all to the context - Thragg is quite literally the most feared man from the viltrumites, even Conquest doesn't dare to mess with him, he proved even on screen of how scary and brutal he can become, yet why the hell is Kregg so casual about braking bad news to him. Ye, you could say he probably has to and idk his face at that one scene didn't fucking seem 'casual', but I feel like he only seemed frustrated at the news, not fearing of Thragg lashing out on him.
They know of one another's strengths and weaknesses, they know how to work coordinated(Thragg orders, Kregg makes sure the order is done) Kregg was the most loyal one from the viltrumites specifically to Thragg who left Thragg's side because of his descend to madness(also because of beautiful human women) and I feel like Kregg constantly talking about the humans in front of Thragg is a vivid attempt from his part to convince Thragg to stand down and come with them. They knew one another from hundreds of thousands of years ago, they rose to power about the same time (Kregg was an advisor to Thragg after Argall died, it's safe to assume he quickly rose to being the main general after other viltrumites died) and the most important fact I could put down to the table (once again), Kregg looked sad when Thragg dismissed him, Lucan and Anissa, as if he really wanted to convince Thragg that his reasoning on why he saved the woman is worth trying for himself, and, again, Thragg became the most pissed after Kregg started slowly integrating to the society that's not theirs.
I want to say that I know this headcanon is based on very surface level facts from the canon, the basic thing of them being a leader and a subordinate, the fact they talk with one another the most from the viltrumites. I knoow that this could also be interpreted as them simply doing their fucking job, as, yeaaa, Kregg quite quickly switched teams, this time REALLY betraying Thragg and that is a glaring hole in my theory but hear me out -
Kregg is the older brother and Thragg is the baby brother.
How fucking cute is that??🥹🥹