Full Name Nina Williams
First Appearance (Alisa's Adventures in Rockoland) Sleepy Sound Bytes
First Appearance (Barney and the Rocko Squad) Barney Takes Over
Alisa's Adventures in Rockoland Portrayer Mary Elizabeth McGlynn (as Charlotte Bell)
Barney and the Rocko Squad Portrayer Mary Elizabeth McGlynn
"Oh! I'm kind of sleepy! Should I stay awak- zzzzz..."
— Nina Williams, after General Salt updates the logbook.

Nina Williams is a cold-blooded assassin, as well as Anna Williams's older sister and the adult counterpart to Naomi Williams. Like in Tekken: Blood Vengeance, she's the most-trusted bodyguard and close friend of Jin Kazama, and working for the Rocko Squad. Also like Jin and the Rocko Squad, she's opposing Crash Gordon, the Rocko Squad's arch-nemesis. She was the first character to appear in Tekken: Blood Vengeance, but she didn't appear in Alisa's Adventures in Rockoland prior to Sleepy Sound Bytes. As of the nineteenth Alisa's Adventures in Rockoland episode, Nina and her younger sister now possess a sleeping habit. She is also known to be one of Charleston's friends. Exclusively in Alisa's Adventures in Rockoland, her childhood counterpart makes an appearance as well.

Nina also appears in Barney and the Rocko Squad. During the show, she is one of the Never Land Pirates, along with Jake, Izzy, and Cubby. She is one of the three Tekken: Blood Vengeance characters to take part in a team from another television show. The other two characters are Ganryu and her younger sister, Anna.

Mary Elizabeth McGlynn (credited as Charlotte Bell in Alisa's Adventures in Rockoland) voices Nina Williams when she visits Rockoland. Nina's voice actress in Barney and the Rocko Squad is also used in the classic Bloopy's Buddies clips as the voice of Sgt. Lookout.