Cyn

In her youth, Tessa was a very lively and kind-hearted individual, although somewhat morbid, hinted at by the décor in her room. Young Tessa was asocial, having little to no interest with other humans and didn't know how to interact with them, exclaiming that she had "only ever talked to robots." Despite her parent's dismay, she had an affinity towards drones and preferred to spend her time with them instead. While Tessa was usually seen close to J, N appeared to be her favorite drone. She also enjoyed fixing broken drones and giving them names and human hair, something other humans disapproved of.

As an adult, Tessa (really the Solver impersonating her) was first portrayed as a rather serious and intimidating individual during the ending of "The Promening". From the way the Solver portrayed adult Tessa, she seemed to be overly confident, exclaiming "Human-made security this human can control!" with pride and confidence, despite not actually having control over the Sentinels. Adult Tessa also retained a bit of an immature and childish streak, grabbing and spinning N around as she did when she was a child, which yet again makes sense as this was what the Solver was exposed to.

However, when it was revealed that Tessa's body was grafted onto Cyn's, the Absolute Solver completely dropped the imitation act.