Thick begins work in Buckkeep Castle after his mother dies. He is poorly treated, frequently referred to as a half-wit and given only one set of clothing. He is not taught to wash either his clothing or his body.
Thick's learning disabilities and physical features resemble those that occur in Down's Syndrome. He is short and has small, heavily-lidded eyes, small ears, and a tendency towards pudginess. He displays some cognitive impairment, including poor memory, limited vocabulary, and difficulty understanding complex concepts.
Thick is extremely talented in the Skill, to the point that he continuously Skills out a "music" composed of a tune his mother used to sing to him and the sounds he hears in daily life. Suppressing this music requires great concentration from him. He also has a tendency to Skill out his negative feelings, which affect those around him.
Fitz first observes Thick being hassled by several stable boys, but immediately forgets about the encounter. Later, he discovers Thick working in Chade's room. Thick dislikes Fitz and Skills at him to try to repel him, also referring to Fitz as "dogstink," "dogstinker," and "dogstink man" at various times. Fitz discovers that Thick is very strongly endowed with the Skill but unable to process all he perceives with it, leaving him distracted and seemingly unintelligent.
Thick becomes an unwitting accomplice to the Piebalds, who intimidate him into spying on Chade, Fitz, and Lord Golden for them. Thick is rewarded for his information with a handful of coins, which are promptly taken from him by the Piebald's stableman spy at Buckkeep Castle. When Fitz discovers this, he prevents Thick from visiting the Piebalds in Buckkeep Town, and shortly thereafter kills the Piebalds living there.
At Chade's urging, Fitz invites Thick to be tutored in the Skill, promising Thick several things that he requests: a red whistle on a green string, a pink sugar cake, candied nuts and raisins, and other items. Thick eventually accepts Fitz's kindness, even allowing Fitz to bathe him and cut his hair. Dutiful also manages to win Thick's loyalty as their Skill lessons progress by being kind to him. As Thick's position becomes stable, he becomes calmer, happier, and fatter.
Thick accompanies Dutiful to the Out Islands, where he discovers he experiences seasickness, which makes him frustrated and mean. He becomes difficult to control and keep calm, and he unconsciously radiates his bad moods through the Skill, to the detriment of crew morale. After the quest is completed, Thick refuses to sail back to Buck, instead returning to Buckkeep with Fitz through the Skill-pillar on Aslevjal. With the creation of Nettle's Coterie, Thick remains in service to Dutiful as a solo Skill user.
Fitz and the Fool Trilogy Edit
Though Thick still serves King Dutiful at court, he is older and his body is beginning to fail him. He has learned how to control his music.
When Bee arrives at Buckkeep Castle after being rescued from the Servants, she overhears Thick's music at night and seeks out the source. Thick is delighted to have a companion, especially one who also knows Fitz. Thick teaches Bee how to create her own Skill-music and enjoys sharing simple, childish pleasures with her. Nettle approves of their friendship, but warns Bee not to meet Thick at night anymore, as it appears unseemly.