He Knew From The Start

The Feld Dragon

"why..... why does it have to end like this I had it all, loving girlfriend, friends that had my back, kids that...(cough) wanted to be just like me when they grew up, as strong as me, grown men who admired my strength, young ladies who wished to be with me" said issei as he lay bleeding from the mortal wound taken by Cao Cao

"Ha-ha finally the wyrm dies.... (breathing heavily) finally I Cao Cao was able the best the strongest devil those disgusting vermin had and they will finally see me as the strongest Hero ever!" said Cao Cao

"If i am to die then you will follow me to the depths of nothingness" said Issei as he could barely lift his arm for one more Dragon Shot, Cao Cao seeing this could not react quick enough, after 9 days of continuous battle with the arguably strongest wielder of the Longinus Boosted Gear 

"NN-" was all he could say before taking a direct shot to the heart, falling to his knees, the "Greatest Hero" had met his end after receiving a drop of blood from the ouroboros dragon which granted him substantial upgrade to his stamina, durability, and mana

"hehe the one who has the last laugh" said Issei

"laughs the hardest" said Orphis appearing from the void "I hope I didn't interrupt anything important" she said coming closer to the top portion of Issei as he looked into her surprisingly worried eyes

"why are (cough) you here after aiding the Hero and Chaos factions" he said just before having a coughing fit, and starting to come in and out of consciousness

walking up to him and kneeling, putting his head on her lap, "Because ITs seal is about to break and the three greater factions needed to be ready for ITs arrival" immediately  after saying this she stood up and looked up and over her shoulder like if someone was yelling at her for giving SPOILERS, she then looked at Issei on the ground "You were supposed to be the one to finally kill the thing, the thing even God of the bible could not kill, only seal for a time hoping that one of his creations could finally surpass the creator, but that is a story only God of the bible can share"

AT THE SAME TIME

"WHERE'S ISSIE, HAS ANYONE SEEN ISSEI" screamed Rias as she was running though the battlefield where both Hero and Chaos factions sought to break the devils front lines in hell

"RIAS OVER HERE" screamed Kiba after ten or so seconds of sprinting she met Kiba, "he was fighting Cao Cao and suddenly he opened a portal to the dimensional gap and went though, Issie being Issei ran though after him and the portal closed immediately after he past though thats the last I saw and felt his presence."

Rias after hearing this called her brother to figure out where in lucifers' name did he go,                  "Nii-sama we need to find Issei, without him I don't know if we can hold onto this fortress, the barriers are holding but it wont be long till they break though maybe 2-3 days more, and those on the front line outside of the barrier are having a difficult time dealing with the abilities of the humans, we need him!"

"Rias! I know, me and Beelzebub were about to invoke a Dragon gate to summon him and if not summon at least get a general location, but thank the maou that you called we need you to help make this a for sure thing" Sirzechs said relieved that his sister is okay enough to worry about someone else.

Rias feeling a huge weight leave her shoulder and thanking the maou for her good luck, "Okay nii-sama ill be right there just give me a second to give my people some orders and some hope"