On my typical exp multipliers (hs, 30%pend, 15%merc, 10%pot), killing two krexels gives me ~0.5% at 211 for roughly three minutes of work. Golems give me ~0.18%/3min, so krexel is nice for me.
At 200 it would give about 5% which is nothing to laugh at. Speaking of which I should start doing krexel on my merc to get him 201 for lulz
Bookmarks