AN: This chapter may help explain some things that were confusing, For why Issei acted the way he did it is solely because Ddraig took control of his mind in his first use of the Boosted Gear, and as an animal Ddraig tried to force himself on something he wanted
Lore of the World
Eden: Eden was the place of the last battle between the three major factions that ruled all of creation, those being the forces of Lucifer, Satan, and Beezlebub in one corner, the forces of Trihexa, Ophis, and the Great Red, in a second corner, and in the final corner was God, Odin, and Zeus. After most of the forces of all three factions were eliminated the three factions realized that they needed to create peace for a time at least to rebuild their forces. To solidify the Armistice the three factions created a new faction to hopefully stop any further wars as they all would fear to hurt their creations. This new faction was created with three individuals, being Adam, Eve, and Lilith, one made by each faction. Upon their creation the three factions made the area of Eden a holy place to never be disturbed by war ever again.
Adam: Adam, the first human male was the creation of God, Odin, and Zeus and gifted by the other two factions to lead their creations. Promised that as long as he did not seek conflict with either of the other factions he would be blessed to be immortal and have power over the factions in any time of war. In time he would go and due to the pressure of Trihexa attacked a Devil who had entered the area of Eden. Saddened by this the factions cast him from Eden and a new war began, but with the Promise that one day a descendants of his would regain Eden by bringing all the factions together. Adam had three sons, Cain by Lilith who sought to destroy all of the factions for casting out his father and mother from Eden, Abel by Eve who wanted to bring all of the factions together, and Seth by Eve who saw that it was not for many millennium before one would unite the factions, but wanted to keep the temporary peace of the world.
Cain: Once his father's death he cursed his mother to be his bride and found partial immortality allowing him to live for a long time and for his soul to move down to his next descendant. He killed Abel in hopes that with Abel dead, the factions would never come to peace and he would one day be able to destroy them all.
Dragons: After Adam's fall the three factions remained at peace, with The Great Red and Ophis leaving the realm, along with most of the remaining dragons. Those who remained with Trihexa were mostly uninteligent beings with the lead exceptions being the young Ddraig and Albion. These two became a large influence who upon being scorned by Mnantina, the eldest and only child of The great Red, blamed it on the leaders of the three, now four factions and attacked them. In response to this their bodies were destroyed and their teenage souls bound to the descendants of Adam, becoming the first two sacred gears.
Sacred Gears: Created by God, because of his loss of strength of his faction when Zeus, and Odin withdrew from the second age of wars due to lack of strength. These gears held the power to harm deity powered beings. Upon his binding, to eliminate the uncontrolled third faction, God vowed that the heir of Eden would be able to command all of the gears and take them from those unworthy to use them.
AN: Hope this explains some things, anything else you want explained please review and I will update this as needed.