Plo Koon is one of the main characters in the Star Wars universe.
Jedi Master Plo Koon is a Kel Dor, born on the planet Dorin. When he is not on the planet's surface, he always wears his goggles and breathmask, so no one knows his hidden face.
Prior to the start of the Clone Wars, Plo Koon was one of many Jedi stationed on Pentraki Arena who tried to prevent the execution of Obi-Wan Kenobi, Anakin Skywalker, and Padmé Amidala. Fortunately, they were all rescued by the Galactic Republic, and the Clone Wars began shortly afterward.
After the war began, Koon helped Skywalker and the Padawan Ahsoka Tano stop General Grievous aboard his giant airship, the Malevolence, from destroying the Outer Rim medical base. Meanwhile, he required reinforcements to finish the ship off, but the transmitters were being jammed by the Droid army. However, thanks to Skywalker's tricks, the Malevolence was finally destroyed.
The following year, Koon recieved a distress signal from Adi Gallia, and he flew to Grievous' destroyer, with the help Commander Wolffe and a small detachment of Wolfpack troopers. He rescues Gallia, along with C-3PO and R2-D2, who were probably also taken hostage.
Above the skies of Cato Nemodia, Koon lead Captain Jag and a few Clone pilots into battle, when suddenly, Order 66 was executed by Chancellor Palpatine. The clones fire upon Koon, and blasted the Kel Dor Jedi out of the sky.