During the Clone Wars, Ahsoka Tano was Anakin Skywalker's Padawan learner, his apprentice in the ways of the Force. The young Togruta girl was discovered by Master Plo Koon and raised in the Jedi Temple. She graduated to Padawan at an early age, in part, as an effort by Master Yoda to teach her new Master, Anakin Skywalker, a greater sense of responsibility. Ahsoka is eager -- almost overly so -- to prove herself worthy of her status as a Padawan, to make Anakin proud, and to become a Jedi Knight.
As Anakin Skywalker's apprentice, Ahsoka is learning a lot while in the thick of combat. She is as daring as her Master, and not against bending the rules if the situation calls for it. Conversely, Anakin is learning his share of lessons too -- ironically, since Ahsoka has been raised in the Jedi Temple since infancy, she actually has more experience learning among Jedi than he does.
It was Jedi Master Plo Koon who found Ahsoka as an infant and recognized her Force potential. He brought her into the Jedi Order, and has kept a watchful eye on her progress. Ahsoka often greets Plo Koon with a friendly Kel Dor phrase, "ko toh ya."
Jedi Master Yoda assigned Ahsoka to be Anakin Skywalker's Padawan in order to teach the impulsive Jedi Knight how to emotionally let go of someone. In time, Yoda reasoned, Anakin would have to accept that Ahsoka was independent and learn an important lesson.
Ahsoka holds the rank of commander in the Republic military, and is served by Clone Captain Rex of the 501st Battalion. Rex at first did not know what to make of the overly eager youngster, but he now has come to greatly respect his Jedi commander.
During a secret diplomatic mission to Raxus, Ahsoka met Lux Bonteri -- the first non-combatant Separatist she had ever truly gotten to know. Likewise, Ahsoka was the first Jedi that Lux had ever met. Their time together helped reshape their ideas of what was formerly simply a faceless enemy.