>>283594857
A little more poetic in Japanese. 終わりのある事がわかったからな! (Owari no aru koto ga wakattakara na!) or "Because I know there's an end to it!". As for the pun, the original line was 便利な腕だな。(Benrina udeda na.), so "That's a useful arm." Well, at least it is Hyakka saying it rather than Mao or something.