Hole in the back of the slime cave, Autocrat's Husk, and more will be coming in future updates. We planned and began a lot of stuff with this update, but we won't be implementing those things until later...!
And... the mercenary commander definitely isn't a cameo, here's there to stay. If you're thinking of something else as 'Izike', then I assure you it's just a coincidence. No drone OVERLORDs in GROVE... yet.
Thanks for playing though, and for the excitement and interest in more! Hope we'll be able to please you when that time comes