Mostly Falkovia vs. everyone else, especially Darkon and occassionally Barovia, but part of his curse being stymied and suffering intolerable losses. Still, just about any Darklord that was a ruler would jump at the chance to absorb another realm into their own - with a few exceptions (like Anketepot).
Because of Borca’s position “on the road” to Barovia, it was a realm that had to deal with a threat of invasion from Falkovia, thus part of it’s write-up involved attempts to appease or keep Falkovia at bay, which disappeared when the realms went to “islands”.