Oni Oni no Mi, Model: Behemoth

Introduction
The Demon Demon Fruit, Model: Behemoth is of the Mythical Zoan class of Devil Fruit, belonging to an incredibly rare form known as the Demon Demon Fruit. It was eaten by "Eclipse" Yeren, the Captain of The Collosal Pirates.

Usage
The main usage for the Demon Demon Fruit, Model: Behemoth is to tremendously increase one's size, physical attributes, and to bequeath to the user, magical and demonic powers.

Strengths
The main strength this Devil Fruit grants is the ability to become the feared demon from Hell, Behemoth itself. What this entails is the ability to increase one's size and physical powers through the roof, and to obtain evil magical arts, such as breathing hellfire and commanding evil spirits to do one's bidding. The size enhancement is so great, that if the user were to transform into the full form of Behemoth, they would blot out the sun and cause darkness in the immediate area. The size of the fully transformed form is equivalent to double the size of Oars or Oars Jr. The physical enhancements have also been rumored to be enough to make the Earth itself shake, though noone has confirmed this, since it'd be too dangerous to try.

The physical properties alone make the user too strong for any ordinary foe, only amazingly skilled and powerful users can fight and possibly defeat such a horrible opponent. To add to it, the user will gain demonic magic, capable of doing many various arts related to witchcraft and sorcery. This can range from summoning and breathing hellfire (which appears as a blackish-purple flame,) to possessing other people and animals for the user's own purposes (only while in a transformed state however. This is done mentally, not spiritually.)

Weaknesses
The user suffers from standard Devil Fruit weaknesses. The only other known weakness to this fruit is that the immense power of Behemoth itself is too mighty and wicked for any mortal to fully master, leaving the fruit unable to be succesfully mastered. If the user transforms into any form of Behemoth, the evil spirit's power will try to control the body, forcing the user to go on devilish rampages, killing friends and foes alike, as well as doing severe harm to the user's physical, mental, and spiritual states. After a struggle to transform back into the user's default form, the user will become terribly exhausted, causing the Devil Fruit's power to become more of a last-ditch effort power for those with average or weak constitutions. Stronger people may be capable of going on after using the fruit's power however. And furthermore, while the user is in his/her hybrid form and becomes agonized by Behemoth, the full form is worse, and will do much more harm and destruction.

Attacks

 *  Hellfire:  This is the standard attack name for when the user decides to breathe hellfire onto his/her enemy(ies.) The flame is intense and unquenchable, and because of the evil magic that engulfs it, the user's hellfire is capable of snuffing out physical flames and lava. There are only a few things capable of standing up to it, mostly anything that negates Devil Fruit powers, and anything associated with God, Heaven, or holy things.

Trivia

 * It's been rumored that anyone who eats an Oni Oni no Mi will be dragged into Hell upon their death. It's been said that each model is watched over by their respective demon. Obviously, this means that once the user dies, s/he will be an eternal slave to Behemoth (or at least, that's what the legends say.)