//option 1

public void Npcdamage(NpcDamageEvent Evt){
    //all code for damage here
}


//option 2

public void NpcDamageNotFromPlayer(NpcDamageEvent Evt){
    //return if it is damage caused by player
}


public void NpcDamageFromPlayer(NpcDamageEvent Evt){
    //return if it isnt damage caused by player
}

// option 3

public void Npcdamage(NpcDamageEvent Evt){
    if(playerdamage){
        npcdamageplayer(player);
    }else{
        npcdamageelse();
    }
}

public void npcdamageplayer(Player player){
    //code for damage to npc from player
}

public void npcdamageelse(){
    //code for damage to npc other than player
}