|Romaji Name||Ōribia Petoriro|
|Alias||Guardian of Emerald|
Thunder Tits (by Kaichi)
|Height||173 cm (as Olivia)|
177 cm (as Klarissa)
|Eye Color||Blue (as Olivia)|
Purple (as Klarissa)
|Hair Color||Blonde (as Olivia)|
Green (as Klarissa)
|Affiliation||Guardians of Hearts|
|Game||School-Side Reservoirs: Chronicles of Hearts|
|Japanese VA||Rina Satou|
Olivia Petrillo (オーリビア・ペトリロ Ōribia Petoriro) is the human form of Klarissa (クラリッサ Kurarissa), the Guardian of Emerald protecting Leanbox. An obsessive video gamer, Olivia is usually mature with a calm composure and is generally friendly. She prominently acts as a motherly figure to the other Guardians of Hearts.
Unlike the others, Olivia doesn't have any siblings, but she develops a close relationship with her apprentice, Makoto. Though, she tends to slip into "creepy sis mode" on him, much to his horror. She is also the third and last Guardians of Hearts to join the party.
Olivia is noticeable for being the most curvy (and busty) of the female members and is the oldest one out of the main cast. She has long curled light blonde hair with long bangs neatly framing her face. Her hair is neatly tied behind with a green-white hairbow with a light green circular piece on it. She has sad blue looking eyes, usually not full open.
Olivia wears an emerald dress with gold markings. Along the top part of her skirt is a big peach/orange bow. Around her neck, she wears a white choker-piece with green lining around the bottom and a very thin white cloth connecting the dress and neck piece together. At the center is a gold circular piece with a small dark green gem in the center and a tiny red ribbon with gold in the center. She also wears golden bracelets on her right wrist and white heeled shoes.
In School-Side Reservoirs: Chronicles of Hearts 2 - Victory, Olivia is now wearing a different off the shoulder dress. It is a dark sea foam-teal color with puffed somewhat sleeves and black spiked cuffs at the end. Her breast still show but have very thin light green straps connecting to her choker-piece around her neck, resembling the belt she wears. The dress covers her lower half and goes between her legs, while the back part is much longer with spiked lining. Around her waist she has a black belt like piece with green circled pads on each hip, connecting to a very light blue ribbon/sash. Her hair also gains a matching colored hairbow (black-green than green-white), while on her neck she has something matching the belt. Her shoes are black slip on's with same pads at the toe and ballerina-like wrappings around the leg.
As Klarissa, Olivia's light blond curled hair is now longer and straight worn in a ponytail, now colored sea-foam green colored. She kept the same ribbon to tie her ponytail. Her eyes keep their shape, albeit smaller and now light purple in color.
Klarissa wears a military-styled dress, sea-foam green in color, which is different than the other Guardian's attire. The dress also incorporates silver futuristic lining in order to match the others. The dress also shows the upper parts of her breasts. The lower part of the dress is cut up on the right portion, which shown she wears a black leggings underneath the dress. Her sleeves are also detached, puffed and white spiked cuffs at the end. Around her waist also has a white belt like piece with green circled pads on her hips. It's also include a dark green cape that nearly reaches her waist. She also dons a thigh-length silver armored boots with green linings.
In Victory, Klarissa's appearance is also changed. Her hair remains the same, but seems to have lengthened somewhat and is much more spikier. Her ribbon also matches the same as her human form. Klarissa's dress is now colored darker and dons a green and black theme than green and white ones. She also wears black fingerless gloves now and her boots are colored black with silver linings.