This can take a moderate amount of dev time, but it will make the game more lively and indepth, boosting the player count. The optimization can be improved by the wildlife being client sided.
PvP progression:
PvP can make the game even more nonlinear. Doing hunts for slayers happens via crow, the player's location shows, and the slayer goes hunting for them.
Doing hunts for demons via Muzan, the player's location shows, and the demon goes hunting them.
Sub classes requiring player kills to obtain
Gamemodes happen during midnight or at some time of the year.
Players getting exp for fighting other players in general.
This can take moderate - high dev time, but can make the game really fun and nonlinear for the player, therefore boosting the player count. The optimization can get worse for the game modes tho.
NPC demon hunting mechanic:
Similar to how in Demon Slayer Muzan made demons hunt Tanjiro to kill him. This can be implemented as an event or like a wanted level.
This can take **moderate **amounts of dev time and make the reputation mechanic more indepth. Making the player more intrigued in the game.
Teleportation currency change:
By the looks of it in the dev log you need 2K yen to teleport. Giving a pillar money to get teleported seems kinda lame, easy, and may ruin exploration(depends if the map is big or not).
Here are ideas on how to make the player think before teleporting:
Idea 1- Yen gets replaced by an uncommon item called "teleport crystal" found in chests.
Idea 2- Teleporting too much gives you insanity.
Idea 3- When you teleport, you need to wait 15 seconds.
This takes minor amounts of dev time, but it **won't **affect the player count.