User blog comment:Sunako30/Who is your top five strongest characters in owari no seraph in your opinion/@comment-33177490-20160102170840/@comment-25942629-20160103012344

It looks like Mahiru was born with Asuramaru inside her. It seems like he was inherited from her demon-possessed mother or something. When she extracts Shikama Doji from Shinoa, she has two demons inside her for a period of time and goes really nuts. Then, she hides Asuramaru inside Guren (much to his surprise) and later gives Shikama Doji to Guren to give back to Shinoa. By the end of the sixth-volume, she no longer has any demons inside her. Assuming all the info I have is correct, of course. There's only her own corrupted personality left behind, which then becomes Mahiru-no-yo at some point.