Gollum
Gollum is a fictional character from J. R. R. Tolkien's legendarium. He was introduced in the 1937 fantasy novel "The Hobbit", and became an important character in its sequel, "The Lord of the Rings". Gollum was a Stoor Hobbit of the River-folk, who lived near the Gladden Fields. Originally known as Sméagol, he was corrupted by the One Ring and later named Gollum after his habit of making "a horrible swallowing noise in his throat".
Aragorn
Gandalf grew suspicious of the ring belonging to the hobbit Bilbo Baggins, which was later discovered to be Sauron's One Ring. Gandalf asked Aragorn to track Gollum, who had previously possessed the Ring. This hunt led Aragorn across Rhovanion, and he finally captured Gollum in the Dead Marshes northwest of Mordor and brought him captive to King Thranduil’s halls in Mirkwood, where Gandalf questioned him.