Gwess

Jolyne Cujoh's cellmate in Part VI: Stone Ocean. She is introduced as a minor antagonist, but stays neutral with friendly tendencies after Jolyne defeats her

Gwess first gives the impression of someone sweet and kind. Originally, she was seen with a "pet" she made talk and gave treats to. If it refused, her personality quickly changed into a mad-driven woman capable of killing for fun. She also has no problem with tricking others but is nevertheless a coward. Unaware of the nature of stands, she didn't participate in any battles following her conflict with Jolyne and resigned herself to read magazines and otherwise act subservient toward her roommate. When Jolyne was under the effect of Miu Miu's Jail House Rock, Guess hardly talked and was very timid.

(Source: JJBA Wikia)