Where Can I Find Merlin Mordred Fanfiction Focused On Their Rivalry?

My method's a bit old-school. I go to FanFiction.Net, pick the 'Merlin' category, and sort by favorites or reviews for stories over 100k words. The epic-length fics almost always have to deal with the Mordred prophecy in detail, and Merlin's interactions with him are necessarily complex. You wade through a lot of Merthur romance, sure, but the payoff is those long, novelistic chapters where the rivalry simmers for ages before boiling over. It's less targeted, but the depth is usually better.

Oh, the Merlin/Mordred rivalry is severely underrated. Everyone's so busy with the main ship they forget the most narratively interesting conflict. For a concentrated dose, I'd skip general searches and go straight to AO3's collection feature. Some fans have made collections specifically for 'Merlin & Mordred' (platonic) or 'Merlin/Mordred' (shipped) fics. That's where the curated stuff lives. Also, look for fics tagged 'Canon Divergence - Season 5' or 'Mordred Lives'—those often explore their dynamic beyond the fatal stab, which usually amps up the rivalry and complex feelings. There's this one author, Lishan17, who writes almost exclusively about Mordred and his relationships; their work is a goldmine for this. Don't forget to check the bookmarks of people who comment on fics you like—that's how I found 'A Heart's A Heavy Burden', which is entirely from Mordred's perspective and seething with this brilliant, quiet jealousy towards Merlin's power and position.

Try searching 'Merlin Mordred enemies' on Tumblr. A lot of writers post snippets or moodboards there, and if you reblog or ask nicely, they'll often link to their full fics on AO3. The tags #merlin fanfiction and #merdred (the ship name) can have some good leads. It's more of a scavenger hunt than a library, but the community vibe can surface stuff the big platforms' algorithms miss.

Finding those stories can be like pulling teeth sometimes, because the main fandom push has always been about Merlin and Arthur. Still, the tension between Merlin and Mordred is what keeps me up at night—that tragic inevitability, the sense of a student destined to destroy his teacher. I've had the best luck on Archive of Our Own by using very specific tag combinations. You absolutely need to filter for the Merlin/Mordred relationship tag (the slash one, not the '&' one if you want rivalry with romantic undertones). Then, I add the 'Angst' and 'Canon-Typical Violence' tags. Excluding the 'Fluff' tag helps a lot too.

Often, the real gems are hiding inside longer Merlin/Arthur stories where the Mordred subplot is incredibly well-developed, almost a story within a story. I remember this one epic, 'The Once and Future King', where Mordred's chapters were so charged with resentment and twisted admiration that I'd skip ahead to read them. Sometimes you have to dig through the main pairing to find the side-dynamics that actually resonate more. I don't use Wattpad for this at all; the tagging system is too chaotic for such a specific dynamic.

I've also found a few really dedicated writers on smaller, older sites like FanFiction.Net by searching for 'Mordred-centric' or 'Mordred Redemption' and then seeing if Merlin features heavily as an antagonist. The rivalry is often framed from Mordred's POV there, which offers a completely different flavor. The key is patience; I've bookmarked maybe ten perfect ones over five years.

I actually disagree with the premise that you need to seek out 'rivalry' specifically. The best explorations of their conflict are often embedded in fics where they're forced into uneasy alliance or mentorship gone wrong. Searching for 'rivalry' might just get you shallow, confrontational stuff. Instead, look for tags like 'Complex Relationships', 'Morally Ambiguous Merlin', or 'Mordred's Perspective'. A story where Merlin, out of guilt or strategy, tries to guide Mordred after he joins the knights creates a far more layered and tense rivalry than just shouting matches. That slow-burn distrust, the moments of almost-connection that sour—that's the good stuff. I found my absolute favorite, 'The Seer and the Sorcerer', by looking for 'Canon Divergence' and 'Magic Reveal' fics, because in those, their dynamic as the two most powerful sorcerers in Camelot gets radically redefined, and the rivalry becomes a desperate, tragic dance.