Sisseri Deo was a Padawan of the Firrerreo species, and male, who served the Jedi Order as the Galactic Republic neared its end. During the concluding period of the Clone Wars, Deo was based at the Jedi Temple on Coruscant, where he took part in the Jedi Temple Apprentice Tournament in 19 BBY.
Recognized as Force-sensitive, Sisseri Deo was brought to the Jedi Temple on Coruscant by a member of the Acquisition Division so he could undergo training in the ways of the Jedi. While at the academy, Deo was part of a clan where he studied until he graduated and became eligible to be the apprentice of a Jedi Master.
While the Clone Wars raged on, Deo remained stationed at the Temple and competed in the Jedi Temple Apprentice Tournament of 19 BBY. Under the administration of Master Ilena Xan, Deo achieved victory in the first two rounds, defeating Forzi Ghul. However, he was eventually defeated and eliminated by Padawan Tallisibeth Enwandung-Esterhazy after she temporarily blinded him using a cup of muja juice.