The Shield of DxD (Tate no Yuusha no Nariagari x Highschool DxD)

Tate no Yuusha

Let us rewind the clock a tiny bit. A thousand years, to be exact, when the flames of war ignited the Three Factions, risking to burn the world.

Humans weren't going to sit still and let them go at it, and so the Four Cardinal Heroes' legend began. Those were four chosen humans, destined to wield the Legendary Weapons, masterpieces of human craftmanship.

A bow, a sword, a spear and a shield. They became humanity's trump card, their insurance policy against any assault from the factions. This – expectedly – angered the devils and the fallen angels, as well as the angels alike. The very existence of the four heroes was considered a heresy, and it was decided they had to be put down.

But they continued to fight amongst themselves, and bards came to tell tales about the Sword and the Bow Hero's slaughter of a platoon of angels sent after them. Their clash with Michael being an epic fight which caused the Archangel to lose two wings and retreat.

The Shield Hero and the Spear Hero worked in tandem, and their combined might decimated the Devil armies. They felt no remorse in dealing with them as brutally as they did, it was their fault fighting a pointless war and drawing humanity to be caught in the crossfire. Unfortunately Rizevim Lucifer corrupted the Spear Hero, leading him to betray humanity and helping him release 666, the Beast of the Apocalypse even God himself feared so much. The leader of the Fallen Angels, Azazel, pulled his side out of the war, feeling they were too much on the brink of destruction, and the angels did the same.

The other three heroes and one Sirzech Gremory decided to go hunt down for Rizevim and the traitor. When the group was on his way to face their fated opponents they were ambushed by Kokabiel, a general formally under Azazel, who declared his intention to continue the Great War.

They were overwhelmed, but the Bow and the Sword Hero sacrificed their lives and managed to defeat them at the cost of Kokabiel escaping, despite Sirzech's best efforts to kill him. Azazel himself declared Kokabiel rogue.

God did manage to seal 666 back, with help from the allied Heavenly Dragons. They both died shortly after, and God's last act was sealing them into Sacred Gears so that they could continue to live on.

It was then that they were informed of Rizevim's last dastardly plot. He had the Spear Hero kidnap the last heir of the Lucifuge clan, Grayfia, all so that he could force Sirzech to hand the Shield Hero over to him. Despite all odds, the Shield Hero accepted. But not before hatching a plan with another devil he came to respect on the battlefield, Serafall Sitri. Serafall and he would go to rescue Grayfia, while Sirzech would fight Rizevim.

On the brink of defeat the young Gremory broke his limits, and his Super Devil form overwhelmed Rizevim, who escaped thanks to illusion magic casted at the last second. Meanwhile, the Shield Hero and Serafall fought a long and tiring battle with the Spear Hero, and succeeded in killing him and rescuing Grayfia.

The betrayal of the Spear Hero and the death of his other fellow heroes sparked an intense sorrow in him, but this was quelled by Sirzech's gratitude and Serafall's companionship. The Shield then began working with the devils – training their armies as peace returned but warning them that he would've sided with humanity should they be in danger again.

Grayfia fell in love with the Hero, and couldn't bear even the mere thought of him not associating himself with the Factions.

"Tate no Yuusha-sama!" Grayfia spoke excitedly, in front of the cabin that was the Shield Hero's house.

"You are...Grayfia, right? How are you?" the Hero asked, his signature shield resting on his left forearm.

"I...I have something to tell you right now!" She seemed in a frenzy, so the hero felt worried.