Maguu Kenki.
An autonomous humanoid mechanical samurai.
According to the introduction in Genshin Impact, this thing inherited the memories of the founding master of the secret sword style "Tengu Shō," a swordsmanship school from an ancient civilization.
The old man actually happened to know a bit about this thing.
It also had some connection to Master Ei.
Players who follow the official Genshin Impact content should know that the official account once released an image of Master Ei together with a friend.
In that image, the oni girl enjoying Master Ei's lap pillow was named Mikoshi Chiyo.
Five hundred years ago, she was corrupted by the Abyss, lost her reason, and attacked Master Ei. Master Ei, in a moment of softness, only cut off one of her horns before Chiyo vanished without a trace.
Mikoshi Chiyo had an eldest son named Mikoshi Michihiro.
At the time, no one understood why Mikoshi Chiyo had attacked—they only knew there had been an assault on the Raiden Shogun.
So this eldest son shut himself away emotionally, eventually leaving to live in seclusion. The place he chose for seclusion was roughly around Konda Village.
From then on, using Konda Village as his base, he would often head into the mountains to practice swordsmanship whenever he had free time.
There, he encountered a lively young tengu girl from the tengu clan.
What followed was the lively tengu girl and the wooden, stoic eldest son of the Shogun's friend clashing swords as a way of communicating their wills.
He also expressed to the tengu girl his desire to sever ties with his past. The tengu girl dismissed the idea with disdain, but as a friend, she still respectfully gave this Mikoshi Michihiro the surname Iwaakura.
They fought once a year for thirteen years—and the eldest son of the Shogun's friend, Mikoshi Michihiro, lost for thirteen years straight.
In their final duel, he finally matched the tengu girl's speed and won. That victory became the origin of "Tengu Shō."
But the story didn't end there. After thirteen years of fighting, the two had developed real feelings for each other.
The wooden man confessed to the lively tengu girl. In terms of emotion, it felt like things had naturally reached that point, but the tengu girl turned him down because she carried heavy responsibilities for her clan and had a strong sense of duty toward her career.
In the end, she left him with these words:
"Then farewell, Michihiro. Forget about me, and with your sword,
carve out a path that belongs solely to the Iwaakura bloodline."
The old man didn't really know how to comment on it. He could only say that he shipped them, but felt the wooden guy bloomed too early—his affection level hadn't been raised high enough yet.
Back then, if this wooden guy had really wanted to be together, it wasn't impossible.
For example, he could have stayed wooden and told the tengu girl something like, "I don't know where to go right now; I'm a bit lost. For the time being, I hope my brother can show me the way."
Then he could have followed the tengu girl and helped revitalize the tengu clan. Once affection levels maxed out and the right age arrived, a sudden "Bro, you smell so good" moment might have led to kids and everything.
In the worst-case ending, it would still be unrequited love—but staying by his friend's side, living the life of Iwaakura, would have been pretty good too. It would have fulfilled his original wish to cut ties with the past.
You could only say that first loves that actually work out are truly beautiful. Don't ask how he knew it was a first love—judging by how this eldest son shut himself away like a block of wood, he was 100% a pure-hearted big boy.
Ahem, this gossip love story seems to have gone a bit off track. Let's bring the topic back.
Anyway, this eldest son, Mikoshi Michihiro—no, Iwaakura Michihiro—seems to have eventually achieved success in his career.
His "Tengu Shō" became the Kujou family's swordsmanship guide.
And he himself earned the martial title "Dōin," establishing the once-thriving Iwaakura school of swordsmanship.
Alright, after dragging on about this eldest son's gossip for so long, you've probably figured out the point.
The memories contained within the Maguu Kenki are those of this Iwaakura Michihiro.
He possessed human legendary-level swordsmanship, a physique comparable to that of monsters, and could even wield elemental power.
You could say the opponent they'd chosen really was an excellent one.