Okay, so this is actually a niche I’ve spent way too much time thinking about. Liko and Amethio’s dynamic is this intense mix of destiny clashing against personal will, right? One’s literally carrying this ancient legacy they’re just trying to figure out, the other’s got this fanatical drive that’s probably rooted in some deep personal loss or institutional indoctrination. That 'fated rivals but with a weird mutual intrigue' vibe is super specific.
I’d actually look outside of strictly action-adventure series for the best crossovers. Something like 'The Raven Cycle' by Maggie Stiefvater would be wild. Imagine Liko as a Blue Sargent figure—someone young and powerful tied to a supernatural lineage they don’t fully understand, trying to live a normal life. Amethio slots perfectly into a Ronan Lynch-type role: fiercely protective, dangerous, volatile, driven by a personal mission that puts him at odds with the world. The atmosphere of dream logic and hidden magic in that series would let their tension play out in really cool, subtle ways beyond just battling.
Another weirdly perfect one is crossing them into 'Fullmetal Alchemist'. The whole theme of equivalent exchange and the cost of power mirrors their journeys. Liko’s connection to the ancient hero could be reimagined as a philosopher’s stone-like burden, something powerful but ethically fraught. Amethio’s single-minded pursuit, maybe as a State Alchemist or a homunculus, creates instant, morally gray conflict. Their fights wouldn’t just be energy blasts; they’d be debates about the price of destiny and the meaning of legacy, which feels true to their core themes.