|Also Known As||Reina Ryūgū|
|Birthday||July 28, 1967|
|Height||161 cm (5 ft 3 in)|
|Portrayed By||Mai Nakahara|
Rena was born in Hinamizawa as Reina Ryuuguu. She lived in Hinamizawa with her family for several years. However, Rena's mother was offered a promotion that required the family to relocate to Ibaraki. As a result of the move, Rena's father was forced to give up his job and largely became a homemaker. Rena often helped her father around the house with cooking and cleaning. As Rena's mother advanced in her career, she began to spend less and less time at home. Rena's mother eventually became romantically involved with a man named Akihito and began bringing Rena to office parties and similar events in an attempt to deepen their relationship while diminishing Rena's relationship with her father.Eventually, Rena's mother became pregnant with Akihito's child and she revealed the affair to Rena and Rena's father. Rena's mother was intent on marrying Akihito and asked Rena to join their new family. Rena, seeing this as a grave betrayal, angrily rebuked her mother and repeatedly blamed herself for not seeing Akihito as a "bad person" earlier. She destroyed all of her mother's possessions and began to cut herself in an attempt to rid herself of the "maggots" she imagined were writhing around in her blood. Rena became increasingly violent, culminating in an attack at her school wherein she destroyed the school's windows and beat three male students with a baseball bat. As a result of the incident, Rena was hospitalized and diagnosed with dysautonomia. While in the hospital, Rena claimed that she was visited by Oyashiro, who told her to return to Hinamizawa if she wanted to be safe. After her release, Rena and her father moved back to Hinamizawa. Upon their return, Rena decided to change her name. In the English translation, she decides to change her name from "Reina" to "Rena" by removing the "icky" parts of her life. "Icky" starts with "i", thus Rena removed the "i" from her name.
Rena appears as a young girl with auburn hair and blue eyes. Her hair is styled with an angled cut with longs sides and a part on the left side of her forehead. She typically wears her school outfit, a white and blue seifuku with a yellow ribbon. Otherwise she wears a white dress with a deep slit up the middle decorated with a purple bow and sash along with a white hat. She also wears black thigh-high socks with brown knee-high boots.
In the first episode of Higurashi no Naku Koro ni Kai, Rena appears as an adult in a purple business dress suit. She has the same hairstyle, though it is a bit longer, and seems to have grown taller since June of 1983.In Higurashi no Naku Koro ni Matsuri, Rena's seifuku tie has a blue knot that has a small white cross in the center of it, similar to the pin Takano Miyo wears on her left side when she is wearing her black military uniform.
Rena has an obsession with cute things, and often attempts to "take them home with her", whether they're hers to take or not. These things can include people such as Rika Furude, Hanyuu, and Satoko Houjou. She spends a lot of time at the garbage dump searching for cute things that have been thrown away. Though she comes off as an airhead, she is often very intuitive.
In contrast with her typically sweet nature, Rena becomes frightening and hostile when angered. Situations that can trigger this anger are be the topic of Oyashiro and lying. The phrase Uso da! (嘘だ！, That's a lie!) has become associated with Rena's character due to how she reacts when she knows she's being lied to. Mion describes Rena as being hostile towards people who make light of or express disbelief in the curse of Oyashiro. This attitude is due to her experience with it and her assumption that Oyashiro physically exists. On the other hand, she, like Rika, often empathizes with and can identify people who are afflicted with advanced symptoms of Hinamizawa Syndrome. It is implied that she feels guilty for not listening to Satoshi's problems before he disappeared.
Rena is shown to be very perceptive and is almost always capable to figuring out when she's being lied to. When determined, she can somewhat understand people just by looking at their face. She claims that she can quickly tell if someone is lying by looking into their eyes. She is also able to form detailed and eerily accurate hypotheses of crime scenes based on evidence observed.
Rena has a tendency to pretend to read as part of a prank but rarely actually does so.During the first episode of Higurashi no Naku Koro ni Kai, an adult Rena appears to have been permanently affected from being one of the few people who survived the events that occurred in Hinamizawa in Tsumihoroboshi-hen.
- Rena directly kills more people than any other character in Higurashi no Naku Koro ni. Rena successfully kills all 15 children attending the Hinamizawa school (including herself) as well as Teppei Houjou and Rina Mamiya.
- The name "Rena" comes from Lenna from Final Fantasy V, known as "Reina" in Japan. This is also where the pen name "Ryukishi07" comes from.
- Rena predates Higurashi no Naku Koro ni; she originally appeared in the trading card game Leaf Fight, an early product of 07th Expansion.
- In the English translation, Rena is the only character other than Miyo Takano who refers to Oyashiro as female. This is likely because she is one of the few who has heard Oyashiro speak.
- The reason Rena is referred to as "Girl A" by the police in Tsumihoroboshi-hen is because Japanese law prohibits the disclosure of the identities of minors involved in criminal cases.
- Rena's name is stylized as Rena Ryugu in the 2020 anime adaptation of Higurashi no Naku Koro ni.