Bozo tells funny jokes about many creatures and has interesting comments about his fellow Thaians. When asked about his job as the Royal Jester, he stops mid-sentence to claim he is the tax collector and asks if you want to pay your taxes.
When asked about weapons, he'll sell you the "Mace of the Fury" (a Rolling Pin for 250 gp), and when asked about magic, he'll ask if you'd like to learn the spell "Lessen Your Load" for 200 gp (and gives you nothing).
He can be related to Rookgaard since there is a grave on the premium side that says:
You see a sign.
You read: Bozo
Jester and escape artist Bozo is a clear allusion to Bozo the Clown, usually shortened to "Bozo" in real life.
With the update 8.1 a new outfit was released, the jester outfit. Since NPC Bozo already was a jester before the update and he became part of the quest to get it his outfit was changed to the Jester oufit. This is how he looked before: