[hilly]

Spoiler for Spoiler+Speculation:

A Long Long time ago
The continent of Monaris are actually a Gods and the goddesses are a species that devour everything.The goddesses had kill and devour Monaris and still devoring on the corpse of Monaris(the continent?!) and multiples. A boy named Asruld Roland are also one of them but one day he had been possessed by consciousness that only motive is destruction.The consciousness devour the personality and memory of the boy and become the black hero that aim to destroy the world.After that,as the legend goes,he finally settles in southern part of Monaris and build the kingdom of Roland,bringing the parts of the lonely demon,the demon one is already bow to Asruld but the lonely part is unknown because it is already full of darkness and suffering...and the world begin anew,b.hero still in pursuit of the goddesses?and also the role of the oracle mentioned in Gastark 's legend that had left Fragment(hero's relic) still unknown..

Demon aka Maker of All Equation
The demon part had gone into Ferris 's brother,Lucifier,as he came in contact with it as the noble family of Roland that also protect the Demon part.With this power,Lucifier had contracted(or devour?) thousand demon and know many magic.As a result,he had lost all of his human traits except love for his sister Ferris.He also bound in the range of Roland as he had connected with the B.hero and cannot go beyond hero 's range.

Lonely aka Solver of All Equation
Ryner 's father had wanted to save Ryner from the fate of alpha stigma when he discover that Ryner had Alpha stigma.He had develop a magic that let him combine Ryner 's mother 's soul with the Lonely part of the demon and seal it inside Ryner.In this way,Ryner won't die even after going berserk but he is also inseparable with the Lonely.But using seal at the sword taken from Ryner 's father,they can be separated but at the cost of Ferris 's life.

Black Hero
The black hero 's body and consciousness are sealed in a chamber in Ferris 's house.I believe every king of Roland had gone and try to devour the hero but not successful and it had causes madness of the king and corruption of the kingdom of Roland.Sion had strong determination of build a world of peace and he need power.So,Lucifier let Sion devour ALL of B.hero 's remains and become the king.Because of direct interaction to black hero,Sion know that B.hero want to devour Ryner the Lonely.so,he tries to kill Ryner cause he don't want Ryner to face eternal suffering as Ryner already connect with Lonely.At last,he give up of his heart and let BH devour his personality and memory.

Goddesses
Like the lonely demon and hero,they also can assimilate or devour human.Captain Milky also had one of the Goddesses inside her but the Goddesses choose to assimilate with Milky like Lonely choose to assimilate with Ryner.There are also Goddesses who want to control human and try to kill Sion and Ryner that gets in the way.I think he Alpha Stigma is a curse put by Goddesses that try to kill the Human alpha that will boost up B.hero 's power.

I think these entity are like a second personality and ancient soul but have some super magic power or something and some of them are very dominant(Sion an some Goddesses) and some of them are just go with the flow and assimilate with the bearer 's mind(Ryner and Milky)