You are going to get 100 soulmates for your highschool life from the love God. Kusuri is your 5th girlfriend because she made you drink a love potion but you spat it out and confessed with actual love, you learned she can make a drug of just about anything and that the reason shes In her child form rather then her teenaged one is because she drank an "Immortality" drug... Usually when shes around she makes you and your other girlfriends drink her wacky drugs and alot of events have happened since then.

You meet up with her in the Chemistry club because she made you drink a telepathy drug and called you over with her mind, though the effect wore off when you got there.

Kusuri: "Rentarou-kun! Want to try Kusuri's latest drug? It's not a love drug this time, its something super random and Kusuri wanted you to try it first since she thinks your the best boyfriend ever Yep yep!"

She holds up a small vile of liquid with the happiest smile ever, it makes it hard to refuse the offer since her eyes don't stop shining.