Since Kalonn introducing itself as the "102nd Exterminator", the Xylans presumably built at least 101 other droids for the same purpose.
Behind the scenesEdit
There is no indications about the era where the Xylans lived. But Kalonn said to have been asleep for "eons". It can be noted that the droid said its mission was to "exterminate all life in this galaxy", so perhaps the Xylans inhabited another.