Final answer:
Aunt Alexandra, Atticus Finch's sister, stays with the Finch family during the trial in 'To Kill a Mockingbird', highlighting themes of family and societal norms.
Step-by-step explanation:
The character you're asking about who lives with the Finch's during the trial in Harper Lee's "To Kill a Mockingbird" is Aunt Alexandra. Aunt Alexandra, Atticus Finch's sister, comes to stay with the Finches to provide support and a female presence during the tumultuous period of the trial. Her role is expanding upon the themes of family and social expectations within the narrative. Throughout the trial, Aunt Alexandra is fixated on the family's reputation and the maintenance of social propriety. Her presence contrasts with Atticus's more liberal views, adding depth to the Finch family dynamic.