PK droids are different from other droids. The player is not able to command them, and they do not count against a player's droid control limit. What they do, is sit in their room and prevent the owner's enemies from leaving. This allows the droid owner to control the battlefiel in a PK fight.
Here are a list of available droids:
These droids are designed for pk fights in the Newbie Simulators. NLRs will stop anyone, but they are easy to escape.
These droids are the most like the original LR5s. They are slightly beefier and harder to kill. These droids stop anyone level 5 and higher.
SLR's bigger brother, in hps and levels. These droids only stop players of level 12 and higher.
XLR is a highly advanced droid of the LR series. XLRs only stop level 19 and higher players. Both HM and non-HM.
ALR is the most highly advanced droid of the LR series. ALR droids stop players level 30+ and are most effective at keeping the highest level players trapped.
You may notice droids are a little hard to lift/throw/intimidate/bash/etc. This is done purposely because way too many people were getting out of them far too easily.
It is dangerous to have too many droid controllers on you when you pk. You can carry 3 controllers around safely. Any number beyond that, and you risk the chance of blowing them all up. Furthermore, opponents have a better chance at slipping your deployed LR droids if you have more than a few in use. The <lrdroids> command allows you to remotely monitor and destruct your deployed LR droids.
The LR series droids now have friend recongition software incorporated into them. What does this mean? It means that you can assign up to 3 "friends" that the droid will ignore and not try to stop when pking. This promotes grouping for PK. Also, with the enhanced AI, the droid will let you know when they have stopped someone if you are on the same planet as the droid. To friend a player to your droid, type 'friend <player>' while you, the player, and the droid are in the same room. You may teach your droid to stop recognizing a player as a friend with 'enemy <player>'. Deployed LR droids can be ordered to repackage themselves into their controller form by way of the <recycle [droid]> command. There is a timer limiting how soon this action can be performed after the droid has been detached.
The LR series droids can now be commanded to self-detonate by their owner. While in the same room as the droid, the owner may <destruct droid> which will cause it to melt down into a pile of scrap. This is done mainly to clear the way for people to move with ease again and has no real combat effect. You can remotely destruct droids using the <lrdroids> command.
Droids no longer cause space deaths, giving the owner credit for the kill and the victim a player-caused death.