- "I am forcing you to face your fear. You won't hurt me, even when I look like this, Edward."
Dating Edward Nygma
After Nygma takes his leave from her apartment the next day, Isabella heads to her job at the Main Public Library. While she is there, she is visited by Mayor Oswald Cobblepot (who had feelings for Nygma) mentioned that Nygma used to be in Arkham Asylum. After brushing up on every newspaper article on Nygma, Isabella later speaks to Nygma and tells him that she is not bothered by his past actions.
Nygma cooked breakfast for Isabella at her home. However, he became unnerved when she put on a pair of glasses resembling Kristen's, and he rushed to the bathroom where he began to hallucinate Kristen in the reflection. Nygma became conflicted on whether or not he should remain with her. Oswald visited Isabella at her house and told her to leave him alone, but she refused after realizing his love for Nygma. When Nygma arrived at her house later on, he was shocked to find that Isabella had done herself up to look like Kringle. She revealed that she found the photos and refused to end their relationship. Seeing this sight, Nygma tried to run out since he was scared of what he would do, Isabella forced him to face his fears and held him close, even getting Nygma to place his hand around her neck. Although it looked like he would snap and strangle her, instead the pair kissed before having sex.
Having had enough of Isabella, a jealous Oswald hired his bodyguard Gabe to cut the break line on her car. When driving down the road and coming to a railroad, she was unable to stop the car and ended up driving in the path of a train, killing her.
After Nygma is informed of Isabella's death, Nygma investigates the area where she was killed. While there, he talked with a homeless man who told him that Isabella's death was not an accident. Nygma investigated further by taking a look at Isabella's vehicle. He discovers the cut break lines and comes to the conclusion that Butch Gilzean must have been responsible for her death.
Nygma takes Butch and his girlfriend Tabitha Galavan hostage. He demands that Butch confesses to killing her, and eventually cuts Tabitha's hand off to make him confess. Butch lies and tells him that he killed her, but says that he shot her in the head, leading to the realization that Butch did not kill Isabella.
Destroying Penguin's empire
Barbara Kean eventually discovered that Cobblepot was responsible for Isabella's death and informed Nygma of her findings. Nygma initially didn't believe her, but after discovering that Cobblepot is in love with him, he realized that Barbara was right. Nygma, Barbara, Butch and Tabitha form an alliance to take down Cobblepot's crime empire.
- "It is a shock. But besides your... odd resemblance to his ex... a certain facility with riddles... compulsion for order... what is it that you two really have in common?"
- —Oswald Cobblepot to Isabella[src]
Isabella was a shy but sweet woman who had a knack for riddles. Her passion for puzzles was a trait that deepened her connection to Edward Nygma. She was also shown to be quite brave as she forced Ed to face his fear, endangering her life in the process.
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