Yarael Poof was an NPC, an alien member of the Jedi Council.
The Phantasmal Malevolence[]
He was present in the Council when Yoda was addressing Qui-Gon, Obi-Wan, and Anakin, telling them the dangers of injecting someone with midi-chlorians to give them Force Sensitivity, which Qui-Gon had done with Anakin. Yoda informed them that people who'd been injected with midi-chlorians in the past had often become unstable, some of them even became evil. Yarael Poof expressed approval of Yoda's lecture.
Revelation of the Sith[]
If Yarael Poof was still alive 13 years later, he was most likely killed along with most of the rest of the Jedi by the Clone Troopers. (In the Star Wars Expanded Universe, he was killed shortly before the events of Attack of the Clones.)