How do I make it so players don't drop their items on death to other players, or allow them to drop items at all? I created donator kits, and my players keep using the donor only diamond armor even after me telling them not to. Please tell me how to as I can not seem to figure out how to myself. Thanks 😁

The FAQ has some useful info on this, make sure you enable restrictions in global.yml and then give out the permissions as necessary.

http://dev.bukkit.org/server-mods/battlekits/pages/main/faq/