This is basically an anti-bot program to eliminate the botters in the game. The Images bellow indicates how this program works:
This is an example how does the Bot-Killer works here in LegacyRO. (If you encounter this scenario please don't panic! You only have to type the number combination in the dialog box that will appear )
This picture indicates the time that you will be jailed. (Npc will come up soon you get jailed)
Here's where you can change the language of interrogatory. (Here you can choose the language that you fluently understand)
And Lastly, Always check your Ranking to view Bots and Bot Hunters, the more accounts that with too much arrest will be permanently banned. (Please always put this in your mind, Reasons may vary)
The features of this program is to kick the asses of the Bots in the server. It is obvious that bots are not allowed in the game, so why use it eh?