Hi, because your demo submission wouldn’t actually have any of that yandere content in it, it wouldn’t qualify for the game jam (the most essential rule/theme is to have ‘yandere’ showcased in your entry) ^^;
You are free to submit a prototype of a day where that is explored though, if you REALLY want to submit to this jam this year, but there’s always next year + other yandere-related jams run throughout the year (stained red/dark romance jam etc.)
Hope this was helpful <:D