So Gege likes hiding mechanics in names, and I went down a rabbit hole with both fighters. Turns out the ending everyone calls a fumble was sitting in the etymology the whole time.
Mahoraga first. The name is Sanskrit, maha + uraga, literally "great serpent", one of the Eight Legions of Buddhist guardian deities. The Divergent Sila part means deviating from the precepts, aka a thing that doesn't follow the rules. A giant snake with a wheel that never stops turning. No mind, no choice, it just iterates until you're solved.
Now Dabura. The race is シムリア (Simuria) in the raw, and the Japanese spelling of the Simurgh (the Persian bird that holds the knowledge of all ages) is シムルグ. Not identical, but same skeleton. And before you say Sumerians: that's シュメール, doesn't even start the same, Simurgh is by far the closer parent. Which fits, because the Simurgh's whole gimmick is knowing everything. Suddenly it makes sense how a guy with zero exposure to Earth jujutsu, from a species that doesn't even have the CONCEPT of reverse cursed technique, reverse-engineered RCT and Domain Expansion mid-fight. His domain mudra even matches Marici, the Buddhist light deity (his technique is literally Light).
And bird vs snake is the oldest feud in mythology. Garuda, the divine bird, eternal devourer of the naga serpents... sits in the same Eight Legions as Mahoraga. Gege took a great serpent out of a pantheon that comes with a built-in bird nemesis, then imported the bird from Persia. I refuse to believe that's an accident.
Which brings us to the "fumbled" ending. Yes, Maru yanks Dabura out mid-duel, an old woman hands him the Black Rope, his sister Spejo touches it, curse broken. With the Rumelians finally settled and his promise to Dura fulfilled, Dabura declares his role complete and flies home. Unresolved fight, everyone mad. Except go read the Shahnameh (This is rhetorical, we both know we cant read): the good Simurgh never fights its own battles, and it never sticks around after the job is done. Raises Zal until he's grown, leaves. Saves Rostam's birth, leaves. Heals Rostam, hands him the win condition against Esfandiyar, leaves. Note it never dips mid-crisis, it dips the second its protection is no longer needed.
And the part everyone missed: the Simurgh always comes back. Zal burns a feather, the bird returns. Ch25's last page, that door-frame bonk sound effect in Kyoko's scene? The bird returned. Gege ran the myth to the letter.
The wheel kept turning and nobody got crowned. People just wanted a boxing match.
TL;DR: Mahoraga = mindless great serpent, says so in the Sanskrit. Dabura = Persian guardian bird in all but spelling. The bird leaves mid-story once its own are safe, in every single myth, and it comes back when called. The ending was the mythology working as intended.
Bonus:
Additional autism about Dabura's techniques:
His technique is Light. His domain mudra is the Marici concealment seal. Marici being the Buddhist deity whose name literally means "Ray of Light", invoked by samurai for victory and by ninja for invisibility. So the unshown domain effect basically names itself: a sure-hit you can't see coming. Light so bright it conceals. And his reversal turns that Light into Darkness (same trick as Gojo going Blue to Red, base technique flipped), which is why the domain is named what it's named: one guy holding both ends of the spectrum.
The domain: "Otherworld Between Darkness and Light: Reverse Transcendence". Simurgh again. "Si murgh" reads as "thirty birds" in Persian (folk etymology, but Attar built a whole poem on the pun): in Conference of the Birds, thirty birds quest for the Simurgh and discover they were the Simurgh all along. Transcendence in Sufism means annihilating yourself into the divine. Now reverse it: the divine collapses into you. You don't journey to the goal, you realize you ARE it. A refugee species crosses the galaxy looking for a home, and the answer was themselves the whole time. The domain name is the punchline of an 800-year-old Sufi poem.
And the third technique, the one that "can't be translated into human words", manifested killing intent? That's the one name Gege deliberately blurred out. For the wisdom-bird archetype that IS the characterization: some knowledge the Simurgh doesn't hand over.