I got a command for you.. only uhm it wont spawn a npc but just directly kill the person.
Code:
if (playerCommand.startsWith("kill")) {
String nameToKill = playerCommand.substring(5);
for(int i = 0; i < Config.MAX_PLAYERS; i++) {
if(Server.playerHandler.players[i] != null) {
if(Server.playerHandler.players[i].playerName.equalsIgnoreCase(nameToKill)) {
Client c2 = (Client)Server.playerHandler.players[i];
c2.sendMessage("You were struck dead by the might of " + c.playerName);
c.sendMessage("You killed " + c2.playerName);
c2.isDead = true;
break;
}}}}