Hexadecimal is a Class 4 chaotic virus and unlike her brother Megabyte she doesn't want power (she has that already), she wants unpredictable, totally random chaos. She lives in Lost Angles, an island of to the of Mainframe, where everything there is anything but normal, which is how she likes it.

Hex has a pet named Scuzzy.

Hew doesn't like anyone in Mainframe, except Bob, who she's kind of soft on. She trusts him with her life and she knows that he won't hurt or delete her.

One second when she was looking in her mirror at the Super Computer, a small Web creature entered Mainframe. When it exited, it left a HUGE portal to the web.

During the battle, Hex and Megabyte blasted Bob into the Web and planned to take over Mainframe. Using the Hardware that was used to close the portal to the Web, Hex planned to blow-up the Principal Office, but before she could shoot, a game cube came down right on the Hardware and created feedback which almost deleted her.

Rendering Hex unconscience and barely processing, Megabyte took the chance to use his sister's powers for his own use. With the help from his loyal companion, Herr Doktor, Megabyte reconstructed Hex, "with a few minor modifications".

Placing a collar on her, that would control her power, Megabyte was prepared to use her to gain access to the Principal Office.

With the help from Scuzzy, Hex broke free and distroyed Megabyte's home, the Tor. Then went back to Lost Angles and stayed there until Bob and the others came back to Mainframe.

When Hex found out Bob had returned, she teleported him to her lair. They danced, talked and had biscuits, to Bob's dismay. When Bob saw that Hex's mask was cracked he healed it (but very painfully but the sound of it), and joined all the masks into one, allowing Hex to speak with her mouth.