hogwarts legacy professor onai assignment 1 - Depulso unavailable

[ZozPrime]

I’ve taken out some trolls, the ability still isn’t available.
Am I missing something?

[Dr.Abscondus]

You need Depulso to do the quest. It isn't the reward. You get Depulso from Professor Sharp;s quest. Oh, and you don't need to kill trolls for Onai's quest. You just need troll bogeys which you can buy.