So this might be a dumb question, but what exactly is the Kerrat system, space war zone supposed to be? and why are the borg in that sector?
The Borg have made a presence in the Federation-Klingon Neutral Zone in Eta Eridani Sector Block, and the Federation has to stop them from having a foothold so close to Federation space.
However, occasionally, Klingon players are there too, trying to pillage Borg technology. So the Federation has to stop them as well, thus it is a warzone within the Federation-Klingon Neutral Zone.
Similarly, there is a ground warzone at Otha System in the Federation-Klingon Neutral Zone in Eta Eridani Sector Block, and as wtih Kerrat, there may occasionally be Klingon players there too, thus another warzone.