Todd character Hannah B Williams
Full name Hannah B. Williams
Gender Female
Played by Melanie Leishman
Hannah is the brains of The Gang, and she could be considered a science nerd. At the start of the series she claimed not to have time for friends and boys, but she joined the gang anyway because she had a huge crush on Todd. Todd always acted more or less oblivious to Hannah's advances.

She is smart and hard working, and has saved the day by herself on several occasions. At the start of the series she hated Jenny because Todd liked her, but they later became good friends.

She really wanted to be a scientist like her parents, even though the science teacher mocked her for having no natural aptitude for it. This led her to use the book to create a Homunculus for her science fair project, which turned out to be a small creature that looked a bit like Todd, but acted violently on Hannah's suppressed emotions. This led the Homunculus to kill the science teacher, destroy another team's project, and try to murder Jenny. Todd lured the Homunculus by annoying Hannah in telling him about how he would get it on with Jenny.

Since she kissed Curtis in episode 1x11 so they wouldn't get caught snooping in Atticus' office, she fell in love with Curtis. It wasn't until Curtis was about to kill Todd with his demonic arm that she confessed her love for him, and they have been a couple since.

In episode 2x05 she was the only one not affected by the book's spell, and she suddenly grew a stitch on her stomach, which later expanded into a pentagram, much like The Book's.

Charlotte switched places with her in episode 2x10, making Hannah the Phantom of Crowley High and Charlotte Curtis' girlfriend. She lured the gang into the theatre to sort things out, but had a hard time because it turned out she didn't know Curtis as well as she thought. After Charlotte died, she resumed her position in the gang.

She almost had sex with Curtis in episode 2x11 while at a house party, but Jenny interrupted them because they had to save the day.

In the would-be future depicted in episode 2x12 she was evil and had a piece of Sand Dragon lodged in her skull, which had damaged her brain's capacity for morality and empathy. Also, she had hooked up with Atticus.

When she visited the Retirement Home with Curtis in episode 2x13, she found her parent's secret laboratory, and found out her parents fused the Book of Pure Evil's cells with hers. When Todd sent the book to an unknown location at the school dance, Hannah died because part of her DNA was the book's. At the end of the episode we see that Hannah's parents made several test subjects, and since the chamber for test subject B was empty, it may be assumed Hannah was test subject B, and that the 'B' in 'Hannah B. Williams' indicates she's test subject B. Next, test subject D arises from her incubation chamber, introducing a new Hannah, Hannah D. Williams.