Talk:Dark Souls II/@comment-92.233.38.95-20140426204516/@comment-3492791-20140426211503

That is a gameplay mechanic. After killing the same enemy a number of times they stop respawning. The only way to get them to spawn again is to use a Bonfire Ascetic. Using an Ascetic however increases the difficulty of all mobs in that area to the next NG+ level. Even after this enemies can still stop spawning again, which will require another Ascetic, which will increase the difficulty again, all the way up to NG+7.

It's a choice between being able to farm the mobs for items or potentially making the area untraverseable.