User blog comment:PitchBlack696/Blog: Admins Board/@comment-6050823-20131118132155

Heres the reason why I think the Thousand Blade Mountains gets its name.

蛇王龍の持つ、剣の如く鋭利に尖った独特の鱗. つらなる姿は千剣のようにも見えるとされ、蛇王龍に触れるものはこの剣鱗によって引き裂かれ、古の山々すらも無残に崩れ去る.

This comes from one of its items, which is a Serpent Dragon King's Blade Scale/蛇王龍の剣鱗.