I am trying to create a new minigame (Halfway done) but I have no experience with java

I am using VisualBukkit for creating the plugin... Half of the problem is solved
There are just few problems
1. I want a specific player to randomly teleport like an enderman just before he is about to get killed by a specific player.
2. I want a specific player to get banned when they get killed by a specific player and the killer would gain a heart
I am not able to upload the picture of the codes for some reasons I hope you can help me... you dont have to write down the code. just point me towards a direction I love solving my problems myself. Thank you
I am using Windows 10, and 1.20 version of minecraft

Edit: oh so the photos did get uploaded, anyways in the photos I am using entity instead of a player so that I could better test the plugin by killing cows and seeing whether they would teleport or not. But when I kill them they just die, they wont teleport

 

i dont know how how capable is visual bukkit but i made something similar days ago and keep it fresh
you need this to get the damager
https://hub.spigotmc.org/javadocs/spigot/org/bukkit/event/entity/EntityDamageByEntityEvent.html
that extedns
https://hub.spigotmc.org/javadocs/spigot/org/bukkit/event/entity/EntityDamageEvent.html

Code:

on EntityDamageByEntityEvent
if damagerPlayer is not instanceof player
    return
if damagedPlayer is not instanceof player
    return
if finalDamage < damagedPlayer.health
   return

cancel event
if damagerPlayer is THE_WANTED_KILLER
    ban damagedPlayer
    add health to damagerPlayer or do anything you want
else
     teleport damagedPlayer anywhere
     and remove potion effects, refill health ,hunger etc... must handle the respawn fully by yourself, (or maybe you can kill the player in the next tick and control the location at respawn, maybe the first option is more work but more easy)