Destroying one of the major Core City Factions and getting 3 XP

[Kekus Maximus]

So I've been looking for a way to kill a few JKK members to get their vest without triggering hostilities with other factions, but then I got carried away... and killed the entirety of JKK including everyone on their base, it's surroundings, merchants floor, commons and docks. Coretech and Praetorian are still neutral.

Will that have any effect on the game? Or at least endings? Will the dungeon in the sewers open after warehouse mission if there is nobody to open it?

[ShoggothWhisperer]

This has no effect on the game. The only way to affect what happens with the oligarchs is to support Gorskey and join praetorian, which gives a special ending slide if a very specific set of events occurs.