Rena Ryugu
From Animepedia
Rena is a girl who returned from Ibaraki to Hinamizawa one year ago, and is in same grade-level as Keiichi. She has an obsession with things she perceives as cute—generally, these things are not considered cute by others. Every now and then, she goes treasure hunting in the town's trash heap, searching for "cute" things to collect, and upon finding something "cute", it's difficult to stop her. She has a habit of repeating words at the ends of sentences, most famously kana? kana? (lit. "I wonder? I wonder?") and when finding something cute, she says Haū! Omochikaerī! (lit. "Haū! I want to take it home!"). When in "Take it Home" mode, she comically becomes stronger and faster. Despite this disarming trait, Rena is shown to be amazingly observant and perceptive about the things around her (in Watanagashi-hen, she was able to deduce that both Rika and Satoko went to the Sonozaki house by looking through the contents of their fridge and a flier). According to Mion, while Rena might seem cute herself, people should be careful not to anger her as she becomes quite scary when angered. A year prior to the main events of the series, Rena briefly moved out of Hinamizawa, only to suffer the effects of the Hinamizawa Syndrome and go berserk at her new school before returning. She is especially sensitive about the topic of Oyashiro; in Tsumihoroboshi-hen, her delusions about the god's true nature go so far as to make her take the school hostage, trying to unreasonably force a police investigation into the matter. When she needs a weapon, she uses a large cleaver that she found at the dump (in the anime) or a toolshed (in the manga and game). She abandoned her real given name, Reina, when she returned to Hinamizawa after the divorce of her parents, holding herself responsible and hoping to begin life anew.