Amu the demon of hunger.
She's a demon child that has quite the apetite. However she is not immediatly agressive, quite the contrary she enjoys living among humans and other living creatures ( even tho most of them fear her ), as long as she is fed, she won't be a mass murder demon.
However while she is able to eat ANYTHING, including ores, wood, vegetables, etc, the less 'organic' the food is, the less it will fill her belly. For example eating 10 whole trees is the equivalent of eating a whole chicken for Amu.
And what will happen when she isn't fed ? In this case, she will go through some phases before going mad from hunger :
In this form she is passive and calm. She will not attack anyone out of hunger and will only defend herself if she gets attacked.
She rarely shows any kind of emotion however she is quite friendly and will fill most of her time by searching food to eat.
2. Starving form :
She enters this form if she is starving. It generally occurs if she dosen't eat anything that would satisfy her for a day or uses a lot of energy. While in this state, she is unstable but still somewhat friendly. However, she gets more agressive as time goes and will be needing a lot of food to revert her back to normal.
You better feed her fast or she will reveal her true face...
3. Demon of Hunger
If Amu hasen't eaten anything in 3 days while in her starving form, she will transform into her true form, a giant sized worm of mass destruction.
Her body is so long it could fit in a small village. Many eyes grow out of her body allowing her to see everything around her, but that also means she can get hurt easily, however pain is the least of her worry as now she is starving, a hunger so terrible that her body suffers because of it.
In this form she becomes a true demon, she will destroy and devour anything in her way , leaving nothing behind. Moutains, trees, villages, animals, anything she can devour she will until her body is satisfied. When reaching this state, she could go in a rampage for months, even years or decades. Nothing can stop her, and stories of old recalls her ancient havocs that she would cause upon the world and they would call her the Neverending Hunger.