General
I've made the easiest life steal mod! From the moment the mod is in your server / world it will start taking its effects! Get killed, lose half a heart, kill another player, gain half a heart. Additionally this mod has a overlay option to see just how much health you have left as a number value on the top left of your screen if your default heart system isn't enough.
Commands
To toggle the life steal mod on and off (admin privilege's requirement)
/lifestealtoggle (true / false)
To toggle player overlay(everyone can use this command since only they are effected by the overlay)
/heartshowtoggle (true / false)
My mod discord