Tears of Blood

Finally (full story )

While Anakin was dealing with Council Business on Coruscant and Obi-Wan was handling Grievous, Ahsoka Tano had a mission of her very own. This was not so uncommon after a few years under Anakin's teachings, as Anakin was needed for more and more missions himself, so Ahsoka had to deal with missions on her own, as a Jedi General would. The Council had received word that Ventress was in the Teth System, where she held Jabba's son on her first mission assignment under Anakin. She took a cruiser and followed her. When they landed, she and a squad of clones moved into the monastery. As they took out droids moving through the monastery, Ahsoka felt Ventress's presence.
"Rex," said Ahsoka, "Finish up here. I'm going after Ventress."
"Yes Sir," said Rex, "We'll leave Ventress to you."
Ahsoka moved on further into the monastery, following the Force right to her.
"So, the Jedi have sent a Youngling to deal with me," said Ventress, her voice sounding much older than it was a few years ago. It didn't seem surprising, given her failures over the years had all but forced Dooku to punish her constantly.
"You forget our last encounters," replied Ahsoka, bringing out her light saber, "I am a Padawan. I will soon be ready to take the trials and become a TRUE Jedi Knight!"
"You're overconfidence will be your downfall," said Ventress, taking out her light sabers, "I will slay you here."
"Somehow, I highly doubt that," finished Ahsoka, as they both ignited their light sabers.
Ventress jumped down, her light sabers meeting Ahsoka's, who defended the first blow.

After all the droids were finished, and about 6 clones were left alive, Captain Rex made a silent motion for them to hold position when he received a call.
"Execute Order 66," said Darth Sidious through the communicator.
"Yes, my lord," said Captain Rex, knowing it would mean killing someone he had come to respect.
He signaled to the others to follow him as he led them through the monastery, searching for Ahsoka.
When they found her, she was deeply engaged in battle with Ventress, neither one holding back. He held the troops back from opening fire.
"Let them finish," he ordered, "It's the least we can do for her."
Ahsoka managed to destroy one of Ventress's sabers and was currently working on the other. Before they both were aware of it, they had stabbed each other at the same time. Ahsoka, getting her wits back after the shock, took her saber out and took off Ventress's head.
It didn't matter, as Ventress struck near the heart, and would ultimately claim her life. As she fell down, Ventress's light saber still in her, she noticed the troops moving towards her, Rex in the lead.
"Sir," said Rex, taking out the light saber, "Are you alright?"
"I'm not gonna make it," said Ahsoka, feeling her life become one with the force as she spoke, "Tell the others, I got Ventress."
"Yes Sir," said Rex, stepping back, before Ahsoka stopped him.
"I know about order 66," she said, getting the clones attention, "Thank you for not interfering."
"You earned it," said Rex, "Ahsoka."
"Look after Anakin," said Ahsoka, as she smiled, "Without us, he'd probably get himself killed, or worse."
"Right," said Rex, smiling back.
He stood up and signaled the others to return to the ship and wait for him. They followed. Ahsoka's eyes closed, her smile fading only a bit, before she became one with the force.
"Goodbye, Ahsoka Tano," said Rex, in eulogy, "Jedi Knight."
Rex turned to leave as well, burning down the monastery when he left so Ahsoka can join the Force and no one would be able to bother her again.