[Character Buff]
Complete the related "The Witch's Coursework" quests to unlock the corresponding characters' additional talents. Note that the skills and Constellation effects of some characters will also change when that happens.
In addition, once you complete the relevant "The Witch's Coursework" quests, the corresponding characters will become Arcane Characters, and you will obtain the Arcane Rite effect when you reach a certain number of Arcane Characters in your party, which further enhances your Arcane Characters.

[Unlocking Criteria]
Each "The Witch's Coursework" quest corresponds to one character. Obtain the corresponding character and level up the corresponding character to Lv. {1} or higher to unlock the relevant quest.