Does anyone have an idea for interpretation?

Moderators: Jambo, Moderators
There came a dark night when he and his companions were wandering in the land beyond Anduin, and they were driven by a black rain to take shelter under the eaves of Mirkwood. In the morning, he was gone from the camp, and his companions called him in vain. They searched for him many days, until at last giving up hope they departed and came at length back to Thorin. Only long after was it learned that Thrain had been taken alive and brought to the Pits of Dol Guldur. There he was tormented and the Ring taken from him, and at last he died.