Youngling II was an NPC, a young boy training to be a Jedi at the Jedi Temple on Coruscant when the Jedi massacre began.
Revelation of the Sith Edit
At the Jedi Temple, the Youngling asked Anakin what they should do. Anakin responded by turning on his laser sword. Anakin killed the boy and he and the Clone Troopers with him slaughtered all the Jedi and their Younglings in the temple.