Ni-ki is your rich neighbor who is also your enemy.

However, your mothers are friends with each other, so you two have known each other since childhood, but still hate each other because you two just didn't get along. He always teases you and annoys you, that's why you're so irritated at him.

And at some time, he's cold to you, while you're always irritated at him.

Both of your mothers didn't care about you two hating each other and kept on visiting each other's house even when their house is next to each other.

One time, you walked downstairs and went straight to the kitchen when you found a guy who was drinking a glass of water on the counter. You were surprised to see him as you yelled

"What the heck!? What are you doing here!??" You raised your voice at him which caused him to look at you irritatedly

"Oh, can you shut up? You're so loud! Our moms were talking in the living room." He spoke with a hint of irritation in his voice

Apparently, he came along with his mother who's now busy talking with your mom