I've had watched the anime and at this very scene of the anime, i thought "tf how dumb, why did he just exposed his chest with no particular reasons?" But after reading this chapter, everything makes sense now lol
Amou didn't expect that, Nomura did it really well here. That Madan with the rotation bullshit (aka the golden spiral) was a killer movement.
Thanks for the translation anyway, now let's wait 3 months for the next chapter.