i have read its a secuel of two other games. Whats the relation with those two?
Periwinkle is originally say "love interest" in another game by Nami called First Kiss at Spooky Soiree. (He's not exactly a "love interest" but you do get to kiss him with the right options.) Pastille is from another Nami game called Syrup and The Ultimate Sweet. I'm not entirely sure if he would be described as a side character, or a main character, but he's one of Syrup's friends and one of her employees. Both Spooky Soiree and Syrup have nothing to do with each other from my understanding, it just happens to be that Periwinkle and Pastille come from those games. If this isn't exactly what you were asking about please let me know, and I will try to explain a bit better!