Polypa is an oliveblooded mercenary who takes jobs killing trolls of any caste for a living. Before the events of Friendsim, her hive was broken into by kids on (presumably) sopor who stole most of her belongings and killed her lusus. A psionic broke both of her legs for fun, rendering her immobile. She was trapped in her hive and left to starve, but she was saved by an unnamed tealblood who lived in her neighborhood.

Polypa is very professional and calculated, being very cautious of her actions and trying to not get caught during an assassination. She is shown to be quite adept at her job; knowing how to blend into the crowd right after getting the job done and not drawing too much attention to herself in order to escape notice of the authorities. This is best illustrated just mere moments after the player runs into her: she quickly informs the player the few details needed to act natural, then begins getting into her designated character without a pause. 

She's slow to trust people and doesn't have any quadrants. Before her tragic accident, she could have been a lot more innocent and naive as supported by her relationship advice blog and her bad taste in books. After said incident, she's less inclined to open up to others and has little regard for both highbloods and lowbloods, outright refering to them as scum. She shows a softer side to herself in her good ending, willingly telling the player about her accident and even letting them be her partner in crime. Should the player inadvertently break her trust in the bad ending, however, she will angrily snap at the player to leave, berating herself for ever placing faith in the player in the first place.

Polypa has fast reflexes and carries a weapon with her at all times; the weapon she's revealed to use is a dagger of sorts. This is probably due to her line of work as a hired killer, and since she's not one to shy away from high-risk assassinations, she has to be a skilled fighter to get the job done. She outright states that in order to kill the violetblood, she had to purchase a very expensive dagger and coat it with a similarly pricey poison before stabbing it in a very specific place in order to ensure that her target is indeed killed for good. 

She is also shown to be quite emotional at times, growing quite irate or sad (depends on which ending) after finding out about the death of her contact. But when the player shooshpaps her, however, she calms down soon enough. While she might become overwrought with feelings, she knows better than to let her emotions get the better of her as being overly emotional doesn't do her any favours as a hired killer.

I'd imagine her sounding emotionless most of the time, only showing emotion when overly sad or angry.