Interesting, and it's a pure coincidence.Yep, that frog god part checks out. It was the god of darkness, no less.
https://en.wikipedia.org/wiki/Kek_(mythology)
The term has its origins in the Korean language, as the onomatopoeia ㅋㅋㅋ, in which ㅋ stands for the "k" sounds, like in raspy, stifled laughter. In the real-time strategy game Starcraft, because the game originally did not support the Korean language, the onomatopoeia was written as "Kekeke" which can be translated to "Hahaha" in English.