Ini Miney is first introduced as a student visiting Kurain Village to study their channelling technique during the second case, Reunion and Turnabout, in Phoenix Wright: Ace Attorney - Justice For All. When talking to Phoenix Wright or in court Ini acts like a ditzy girl, oblivious to what is going on around her and not particularly intelligent. When pressured, however, her personality completely changes and she becomes aggressive and more in control of the situation.
Early in the case it is revealed that Ini Miney is the younger sister of another character introduced during this case, Mimi Miney, a nurse that died in a car accident shortly after a scandal involving the death of 14 of her patients.
During Reunion and Turnabout, a murder occurs at Kurain Village while Ini is visiting. When questioned by Phoenix Wright after everything has settled down, Ini claims to have been sleeping in the guest room. While not particularly suspicious, Psyche Locks appear due to Phoenix's Magatama that reveals she is hiding something from him and the number of locks suggest it is significant. Ini then goes on to insists she has no relation to the victim, later to be revealed as a lie.
When pulled in to court as a witness, Ini Miney continues her act of ignorance until she is pressured and goes on the offensive. Noticing a change in her personality, the questioning that follows goes on to reveal that Ini Miney is actually Mimi Miney and has been posing as Ini, who was actually the person that died in the car crash. Due to her severe injuries Mimi required extensive reconstruction surgery, particularly on her face. The accident caused confusion, and she used her sisters driving license as the basis for her facial reconstruction explaining her appearance being identical to her dead sister, Ini Miney.
During the channelling session between Maya Fey and Dr. Grey, Maya was drugged so that a concealed Ini/Mimi could take her place in disguise and murder Dr. Grey, framing Maya for the crime.
The case ends with an explanation of the events of the accident, needing a fresh start after the scandal, her plot to murder Dr. Grey, her accomplice Morgan Fey a definitive admission of guilt leading to her imprisonment along with Morgan Fey.