Rill was a slave and leader of the slaves in the Cloakwood Mine. If you choose to help him, he is instrumental in evacuating the slaves.
Rill is on the second level of the Cloakwood Mine and will hail you on sight. You can pretend to be working for the Iron Throne and force him to get back to work, or you can be kind to him and the others by giving him 100gp to bribe the guards so all the slaves can be evacuated from the mine before it is flooded. There is some advantage to this course, as getting all the slaves out of the mine will get you the best reward on completion of the Cloakwood Mine quest.