I love it
I love that the author stay true to Arwin's nature.
It was quite shocking to see a main character killing a villain but that's because usually attempt murder are never treated seriously in manga. (that's not ok btw)
And I thought he was quite hasty in his investigation but I reread the previous chapter. I think he appeared behind Peridot before strangling her. She was listening to herself talk, proud of her plans and she said she wanted Latte to be "tormented by the terror that you won't be able to escape." And that's exactly what Arwin did to her.
Or I read too much in this and he just went straight for the kill ¯\_(ツ)_/¯ Either way I'm happy with him <3