Yuki appears in MySims Galaxy Wii. She works for MorcuCorp, for the first part. However, when you confront her around mid-point through the game, she stops working for MorcuCorp and joins up with the Fortune Hunters. You, later, see her in the Fortune Hunting Galaxy. She helps them to look for Shinies.
Super Shiny Comet meets the Raceway Galaxy
Objective: Collect the shinies in the time limit.
Notepad Task Dialogue: The residents of the Raceway Galaxy need your help. Yuki has come over and trapped them in a bubble of doom. The only way out is to collect the shinies. Collect all of them to release them.
Notepad Task Conclusion Dialogue: Well done, now there are more galaxies to help! So go and kick some MorcuCorp butts!