The original Erdrick / Persona 5R leak from December mentioned this stage:
Edit 1: more info
- Stage is Alefgard
- Erdrick (Male) and Erdrick (Female), 2 colors each of Anlucia and the Dragon Quest XI Hero
- Slime appears on screen with a skill
- Achieved through active collaboration on Square’s side
- To the benefit of overseas marketing for the DQ series
Edit 2: Home Run Contest may return, strings related to it found (check whole thread).