Twenty-five days.
It has been twenty-five days in the secret realm and more than two weeks of these days, I spent in the core area. It was not nice but I gained a lot.
There were a lot of rare and unknown monsters in this area but I didn't try to tame any of them. This was because I learned a great lesson about taming.
I have to split the EXP I gained with the tamed monsters. So even though it was tempting and this is an opportunity that doesn't come again, I decided not to tame more monsters, until I reached the peak Tier-4.
Even with me hunting in the core area and with my clones spread across the core area, I was only able to reach the peak Tier-4 after fifteen days of hunting in the core area. This was done after I reduced the time that I would rest at night.
