Jedi Master Plo Koon has a significant legacy in Star Wars. A Kel Dor from the planet Dorin, he was a member of the Jedi High Council, and a Republic General during the Clone Wars. Master Plo Koon was the Jedi who found Ahsoka Tano and brought her to the Order. But outside his role as a Jedi, however, he has a distinct and recognizable look, due primarily to the unique mask he wears at all times.
However, because Plo never takes the mask off, few know what his face actually looks like. What's more, Star Wars canon never specifies why he even wears it. But a look into expanded lore, such as concept art and comics, reveals the mystery behind both these questions.
Why Does Plo Kloon Wear a Mask?
The Kel Dors are a humanoid species with the ability to survive in the inhospitable vacuum of space for a limited time. That forces Kel Dors to adopt a mask in oxygen-rich environments. In sharp contrast to most other species in Star Wars, oxygen is actually toxic to Kel Dors. Therefore, they wear goggles along with their masks to protect their eyes from literally melting out of their skulls if they are exposed to too much oxygen. In that way, Plo Koon's mask is actually a life support device.
According to Henry Gilroy, a writer for Star Wars: The Clone Wars, George Lucas thought Plo's face was too weird-looking to be liked by fans. His appearance is certainly unique, but his calm and wise nature help with his popularity. Plus, there is something intriguing and engaging about such a distinctive character design.
What Does Plo Koon Look Like With No Mask?
The above image from the old Star Wars database shows Plo Koon without his goggles. However, the image isn't exactly canon. It's sourced from a behind-the-scenes feature and never appears in any similar form within the films or television series. In addition, it is also a pre-production image, which means there is a good chance it's an incomplete rendering of the character. However, it does give an idea of how Plo can be conceived without a mask.
Plo Koon depicted without the mask and goggles can be found in 2009's Star Wars: Purge: Seconds to Die, a comic written by John Ostrander and penciled by Jim Hall. However, this comic is no longer considered canon because it was published before April 25, 2014.
So, while there is no established canon reference to what Plo Koon, or any other Kel Dor, looks like without a mask, fans can visualize him through both the concept art and his appearance in Seconds to Die.