Cang Xiaoxuan did not keep him in suspense and directly told him the key to its transformation.
"Slay an oni?"
Minamoto Hikari froze.
"That's right. You only need to use it to kill a powerful evil spirit, and it will transform." What Cang Xiaoxuan meant was for Minamoto Hikari to use this sword to kill a ghost—the kind with a spiritual body.
"Oni..."
Yet when Minamoto Hikari heard Cang Xiaoxuan mention a powerful evil spirit, the first thing that came to mind was not a ghost, but... a type of yokai from Japan: oni.
Oni were a type of Japanese yokai. Born with immense strength, they were higher beings than ordinary yokai. Their most famous representative was Shuten Doji... though Shuten Doji might not even have been born yet.
After all, the millennium Heian-kyō in which Shuten Doji was active was still more than two hundred years away.
After hearing Cang Xiaoxuan's hint, Minamoto Hikari committed it to memory.
Although oni were incredibly powerful, and according to Cang Xiaoxuan, he had to kill one that was stronger even among ordinary oni.
Still...
Minamoto Hikari tightened his grip on the tachi in his hand. Rather than fear, boundless courage surged within him. One day, he would surely slay a terrifying oni and make the blade in his hand transform.
"Thank you again. I know what to do now."
Minamoto Hikari had no intention of hunting oni now. Even the most ordinary oni was not something he could handle at present. Warriors capable of killing oni were called oni-slaying samurai... an honor as glorious as slaying dragons in the West.
That also showed just how terrifying oni were, and how difficult they were to kill.
"As long as you understand."
Seeing Minamoto Hikari's serious expression, Cang Xiaoxuan did not think much of