After Ash's Level 3 event, there are new options in the principal's office. Waifu Store and Waifu House. So here in the Waifu House, one of Ash's sinners appears after the event, whose story you need to go through. To do so, you need to maintain her hunger and mood levels. And also buy special gifts to advance the story. All of this will be sold in the Waifu Store. As of version 0.4, a Mikasa bug appears after the Slave Level 3 event for Ash. This bug prevents you from progressing through her story, so fulfilling all conditions can only be done in Ash's Love Route.