Jigoku de Mesu ga Hikaru

Hiromi is mistreated by her family because of her naturally ugly appearance. Unable to bear her situation, she attempts to commit suicide, but is rescued in the nick of time by a genius doctor, Iwao Toshiaki, and is exposed to human kindness for the first time. However, Iwao is trying to use Hiromi's brain to enter the realm of the divine, which is inaccessible to humans...
(Source: Kodansha, translated)