Penevera is the matron of the "companions" at Villa Tisiphone. She is also accompanied by a tiefling bodyguard, supposedly to protect her from unruly patrons.
She is also secretly a succubus who drains unlucky patrons and removes their hearts as a sacrifice to Zariel. At some point, she became trapped in Sithicus and cannot return to Avernus by normal means. Whenever she uses her ethereal ability to travel, she simply reappears elsewhere in Sithicus. She is hoping that with enough sacrifices, Zariel will hear her and rescue her from the domains of dread.
The party encountered her again at the Avrigard Manor on Avrigard Island in Lake Thelen. They discovered that she had been summoned to Sithicus by a spell worked by a teenage boy named Herbert Avrigard. Penevera drove Rolen Avrigard to madness and he murdered his wife Adrianna and Herbert.