|YOU'VE FORGOTTEN YOUR PURPOSE!|
Lulu was beloved by her owner, who wanted to give up his life as a hitman to live peacefully with her. However, Aku later abducts Lulu in order to force X-49 into performing one last mission: to try and kill Samurai Jack, which he failed to do. It's unknown what happened to Lulu, but it is presumed that she was killed by Aku for X-49's failure.
It is unknown how the past Aku's destruction affected her existence. However, as X-49 was supposedly erased from existence, it's likely that her encounter with him never happened.