Board Thread:Questions and Answers/@comment-34057648-20180509050706/@comment-36056916-20180702131414

The Core and Hotland are counted as the same kill count area. For those two, the bridge right before entering Mettaton Neo's spot is ideal for grinding. There is a save directly to the right of the bridge, and monsters usually spawn in groups of 2-3. For waterfall, I recommend the area where you can access Temmie Village. (extra tip, when walking against a horizontal area, such as the bridge before Mettaton Neo in The Core, press both up and down arrows + the direction you want to walk in. It looks really weird, but it spawns monsters a lot faster.) Hope this helped!