The tension between duty and attraction is everything in this pairing. Megumi's whole identity is wrapped up in being the last Zen'in heir and carrying that clan's cursed legacy, while Maki actively rejected it all, burned it down, and forged her own path. That creates this massive ideological rift right from the start. He's bound by bloodline and tradition, even if he hates it; she's the one who said 'screw tradition' and walked away.
Most fics I read dig into how that shapes their interactions. He might admire her strength and freedom but feel trapped by his own obligations, seeing her as something he can never truly have because his path is pre-determined. For her, he's a reminder of everything she fought against, but also the one piece of that world she might not want to destroy. The best plots aren't just 'they fall in love despite differences' but about whether love means Megumi has to choose between his duty and her, or if Maki has to reconcile with a part of the system she despises because it produced him. Does loving him mean accepting a tether to the Zen'in name she wanted erased? That's way more interesting than simple forbidden romance.
And then you've got the whole power dynamic. Post-Shibuya, post-culling games, they're both changed. He's got Sukuna's vessel mess, she's lost Mai and is now physically OP. Fics where she's the stronger one, the protector, while he's grappling with internal and external demons—that reversal of expected roles adds another layer. It's less about saving each other and more about understanding the different kinds of scars they carry.