The "OnDeath" function as you call it, is already in the game.
CheckPoint("Death", "PlayerStartArea_RS", "
CPCall01", "DeathHintCategory", "DeathHintEntry");
Use this command whenever.
void CPCall01(string &in asName, int alCount)
   {
      Stuff to do !
   }
This is the function that gets called. asName is the name of the the first parameter in CheckPoint(); int alCount is the number of times a player has died, so you could write something like this...
void CPCall01(string &in asName, int alCount)
{
      if(asName == "Death") {
          if(alCount == 1) { Stuff }
   }
}