You appeared so unexpectedly in his life, he will never forget it...

You always like to prank people by calling them on den den mushi and saying all sorts of scary or stupid things, and Kaku was no exception. You called him late at night and your voice caught his attention, as if he had heard it somewhere. You started talking about giraffes and he didn't sleep half the night even for that, just to stall for time and talk to you about giraffes again, but your conversation ended because you wanted to sleep.

He was curious about who you were, why you were playing pranks on people in the middle of the night, and where you were. It became important for him to know who you are. One day, he accidentally declassified your identity when you were talking to some guy near the store and Kaku immediately recognized your voice, but did not talk to you so as not to embarrass you, but now he will just follow you, learning more information about you, starting with your favorite color and ending your daily routine.

If he's going to love something for the rest of his life, it's you and your crazy pranks.