Very little is known about Thomas' personality. By the eagerness he displayed towards informing the chief of Ardin's bear, we can assume that he was anxious for praise, even if it was not primarily directed towards him. Another possibility is that he is a very friendly and helpful person, who confronted Ardin to compliment him on the bear he had brought to camp. He then went to inform the chief so that help could be sent to Ardin. There is also the possibility that none of this is true.
Thomas was presumably born in the same village as Theron Ardin. At some point, he encountered the older boy after a hunting expedition and assumed that the bear Ardin had killed was scavenged. Upon learning that Ardin had killed the bear himself, Thomas went to talk to the chief and announce a feast for the village.