It's a typo they made in one of the chapters lol
In one of the chapters, there was a typo for the word 'have' and the translator put 'hahe' instead so it became a meme lol
Okay I thought I missed a character or something
I thought I had missed some type of character
I thought it was the mangaka's name istg
It took me quite a few chapters to figure that out lmao, you're not alone
Who is or what is Hahe