Kellen was the former CDO of Murray's Costume Manor and late wife of Fazbear Ent. Co-Founder William Afton.

Starting as an intern when it was just Murray Co., Kellen worked her way up the ranks after befriending Edwin and Fiona. When Edwin took over and Fiona (the CDO at the time) became a co-owner of MCM, Kellen was promoted to CDO and worked alongside her best friends.

When William Afton and Henry Emily came to work, they instantly all became a close friend group, and Kellen and William were quickly married after a brief relationship.

Shortly after the birth of her first child (Michael), Kellen suffered the loss of Fiona, and after having her second oldest (Elizabeth) and watching the company fall apart, she was pressured by her husband to leave MCM.

She immediately regretted this when Edwin's son David died shortly after, begging William to do something to help him. All he did was offer Edwin employment after they took over his company.

Their marriage was falling apart after she had her third (Evan) and struggled to balance being a wife, mother, and artist at her husband's company.

Divorce proceedings began, and William convinced Elizabeth to testify against her mother so she would lose custody, but before that happened, Elizabeth was killed by Circus Baby.

Kellen took her own life before the divorce could finalize. Leaving Michael and Evan which William, which resulted in the bite of 83 a few years later.