It says "戦うよ。 僕やソーマピーリスみたいな存在が二度と現れない世界にする為に"

I looked up the kanji and stuff and didn't entirely understand what it was saying... Google translate seems to have made some sense of it, though, it translated it as "I fight. In order to present to the world that do not appear again like me and Somapirisu"... So I think it means "I fight for a world in which people like myself and Soma Pieres will never again appear"...
And to nitpick - those weren't square brackets, they were Japanese-style quotes...