Seiichi Takayama 
The Master of Ragnarok & Blesser of Einherjar (Manga) Volume 4 

A Clash of Strengths; A Memory of Weakness

Yuuto’s war with the Lightning Clan comes to a head in a showdown at the river’s edge, but it’s going to take every trick in his book to survive… can he keep not only his own head, but save those closest to him as well? And how did he end up in this mess to begin with?