Alpha!Techno and Omega!Phil.
Alpha Techno, who is physically the very definition of an Alpha - absolutely massive and powerful, with a strong scent able to make even the most dominant Alphas submit to him.
But personality wise, Techno is not a conventional Alpha. He has only the faintest idea how different dynamics are supposed to work and interact based on societal norms, so he relies on instincts. He doesn't try to be intimidating or dominating (unless it's like a battle or something but that's different), and often stays in the background, letting others take the lead. He is respectful of Omegas but wary of them as well, often giving them a wide berth because he knows most find him scary.
Omega Phil, who albeit is larger than most Omegas, but is very handsome and beautiful, with a sweet scent that has a soothing effect on others.
At least, his scent is soothing when he's not the one starting fights. Phil knows well the rules society expects Omegas to follow - Phil just doesn't give a fuck. He's chaotic and bold, unafraid of challenging even the largest of Alphas or acting flippant towards them. Phil is kind and has a soft spot for children, but he is not what one would call nice and is considered extremely aggressive for an Omega. Even dangerous and unfit to be mated.
They're both very different from what society expects them to be, but that's ok because neither of them really care. Especially not when they have each other.
With each other, they can just be themselves. Techno doesn't have to be wary around Phil, worried that he'll scare him off with one wrong move, not when Phil has very little fear of challenging Alphas. Phil doesn't feel the urge to be aggressive and chase Techno off or challenge him, not when he knows Techno has nothing but respect and love for him.
Phil feels safe and comfortable around Techno, to the point that all the aggression he usually has around others, just disappears. He's completely at ease and relaxed, and he has so much trust in Techno that Phil doesn't just allow Techno to see this side of him, but he asks Techno to take the lead and take care of him.
For an Omega as aggressive as Phil to ask Techno that kind of thing, it's a very big deal.
While normally Techno is not one to take the lead, by Phil asking him to, it triggers a very basic instinct of Techno's that he often keeps hidden - an Alpha's natural inclination to serve and protect their mate. Of course, he takes care of Phil and absolutely spoils him - showering Phil in love and affection, giving him countless kisses and unable to keep his hands off of him for very long, often ending up spooning Phil in their nest and purring loudly in content.