Sam went to the Nagin Planet, along with Arman, Chatur and two more humans beside him. No one knew who they are. But they are now wearing the badges of some individual members of the Nagin castle, so no one cared.
The thunder prison tent was taken away. And even the lake was not filled with spirit stones.
After coming back to the Nagin, Sam went to meet with the Emperor while sending the rest of the members who followed him to Mirage city. He met with the emperor and got the rewards he asked for.
He would be gaining ten percent of the whole imperial family's herb harvest every year and this is only one of the ten benefits.
He got some land, a title and some more privileges along with a large amount of spirit stones. He really did get a great deal and Emperor still owed him a favor after that.