The Outcast

Biography
Born on Gallifrey, not much is known beyond that. She did admire the young, First Doctor though, stealing a TARDIS nearly 100 years later but was banished and became know as "The Outcast". After sometime, she began traveling to catch up with The Doctor to abandon her Type 62 TARDIS, to join The Doctor in his. After bouncing to find him, she finally met the 10th Doctor, but realized something was wrong.

Tenth Doctor
After meeting The Tenth, she heard the 2 words she had heard before whilst bouncing the Universe, "Time War". After observing, she realized that they were supposed to be all gone, but through bouncing the universe, she had escaped. She soon met the Tenth, and explained her existence (Opening up an alternate future for her and the Doctor). The Doctor rejected the thought and began to observe, but his TARDIS found she had 2 hearts.

Traveling with the Tenth
The actions of the TARDIS scanning her lead to The Doctor telling the whole story of the Time War, and that she needs to go back to her time, but the TARDIS shows that it is her time and she had flown through a crack in the Time Lock, allowing her to make it out of the Pre-Time War Gallifrey.

After time The Doctor began to start moving the TARDIS, but The Outcast screamed no and said that her TARDIS was left there. This led The Doctor to explain that it will be fine and that nothing can get into a locked TARDIS, especially a Type 62 Mark IV.

They then traveled to many planets, from many Era's and periods. (Which included but not limited: Earth, Klorus, Raxzionius, The Junk Asteroid, Pyrus, Eol-4 (Which was a copy of earth) and Clover.)

Regeneration
Upon landing in 1944, after leaving The Doctor's TARDIS, she had exited and stared at the freaked German soldiers, who killed her and ran from the Red Telephone Box. This triggered Regeneration.

Personality and traits
This Outcast was more friendly and questioned what she could find in the Universe, she also spent much more time looking for a companion after leaving The Doctor's TARDIS.