I completed the main task there, and the stone no longer sparkles
It's not the same area where you fight the shrike boss for the main quest. To get to Morghul's fight, you need to pass through the labyrinth section inside lave depths.
And what if I spent about a chal walking through the maze that is on the left but found nothing
It's on the right and you need to understand how to navigate inside and not run around blindly.
And how to invite Naka and Ren to the hot springs, I opened them and found them in the forest, but I can't invite them
You need to find them chilling in the taverns/inns. Bright Meadows for Naka and Thula for Rena. Both appear there in the evening.
