Woken up by a dripping sound, she found Arnold's corpse and realized her parents were killed, so Reimi saved Rohan by letting him escape by the window while she received a gruesome wound in the back and died.

Who saved Rohan?

During the night of August 13, 1983, his parents had an important thing to attend to and so Rohan was left with Reimi. He was saved by Reimi at the cost of her own life from the serial killer Yoshikage Kira, but was in shock and couldn't serve as a witness.

Was reimi Kira the first victim?

Reimi Sugimoto is Yoshikage Kira's first victim. She was killed 15 years before the happenings of the manga, and waited as a ghost for someone whom she could warn about her killer.