That's Red, not Kotone. Kotone is the blue text - you can tell because both Green and Red are yelling at her to speak in Japanese after she talks. (コトネ日本語でおk!!!)
Brindiamo defines "JKK" as J(=情熱的に) K(=考えたら) K(=こうなった) in the description on pixiv. I'm not savvy enough to provide a proper quality translation of it, though..especially since she only uses "JK!" here.
Common sense, let's all behave sensibly!Kotone, speak Japanese, OK!!!
Red and Green speaking togetherYou're digging your elbow into my chest! You die! Die a thousand times!That's my line! And anyway, I don't even know what you're saying! This is war, asshole -- die! Die a hundred times!Stop pushing on my chin! It hurts!You're too close, you're too close! Gross! You're only pretty when someone's right in your face, so fact is, I'm the better-looking guy here!