Thaddeus Winslow Cooper III was a Cooper thief that lived in England during the Victorian era (1837-1901) and is considered the most chivalrous of the Coopers. According to his entry in the Thievius Raccoonus, he was at the peak of his career in the 1890s.
Like most other Coopers, he left his cane and some other precious belongings in the Cooper Vault. His section of the Vault was comprised of jumping on floating barrels, hook swinging and spire jumping. His most recent appearance was during a train heist in which Sly Cooper used his section of the Thievius Raccoonus containing details on disguise, deception, and charm to bypass security, including Inspector Carmelita Fox.
- Sly Cooper and the Thievius Raccoonus
- Fully restored Thievius Raccoonus cutscene
- Sly 2: Band of Thieves
- A Shadow from the Past (cutscene)
- Sly 3: Honor Among Thieves
- Sly Cooper: Thieves in Time
- Paris Prologue (cutscene)
- Due to his name, it can be assumed that he had a father and grandfather both named Thaddeus Winslow Cooper.
- If you look closely at Thaddeus's page in the cartoon short "Goodbye My Sweet" it has two separate years as to when it was written; 1839 underneath the title and 1893 underneath his picture, though it can be assumed that 1839 was a typo.
- Thaddeus at one point was employed by the Scotland Yard, as his entry in the Thievius Raccoonus states.
- Due to the small gap between which their careers reached their zenith, it is possible that Thaddeus and "Tennessee Kid" Cooper are directly related (Tennessee was active in the 1880s, only a decade before Thaddeus reached his climax in the 1890s).
- During "Final Legacy" in Sly 3: Honor Among Thieves, when Sly talks to Dr. M, Thaddeus is misspelled as "Thadius" in the subtitles.
- Right before the final battle of Sly 3, Sly marvels at Thaddeus' ability to "make a flying machine in the 1800's", indicating Thaddeus also had very impressive mechanical ability.