Outside the barrier, Rossweisse were helping maintain the barrier while reducing the effect of [Infinite seal] that Issei told her about. It was the reason why they are currently able to used balance breaker without problem.
With the [Infinite seal] to sever the connection from the outside She was able provide help by acting as a bridge to ensure Issei and the rest are able to used their power at the fullest. Though, Issei has control over the system Doesn't mean his the sacred gear system itself. He still needed to visit heaven in order to finally gain its last piece.
Issei won't have a problem using his sacred gear but for the others would be different. Rossweisse kept maintaining her connection to Issei while Ophis and Great Red was maintaining the barrier to makes sure that the dark apostle wont be able to escape if it arises.
"I'll make sure to make Issei repay me."
She then sensed killing intent and quickly turn to see a single individual approaching in the distances. It was young girl holding violet parasol dress in Victorian gothic Lolita outfit with her hair covering the left side of her face.
It was gradually getting close with the pressure increasing causing everyone to quiver in fear and purposely sweating. They couldn't fathom how each step sounded like deafening roar.
"Ara~ Ara~ I was expecting more stronger welcoming party to see me."
It spoke calmly that contrast her radiating killing intent towards them. Irene and Albion who was not occupied swiftly moved to attack as the former summoned her dragon flame then instantly boost it by a millions times over while the latter used her dividing power at the new arrival as she tried to strike the young girl but was meant by a thick dark barrier repelling their attack.
Irene evaded her own attack while twisting her body to perform a roundhouse kick to the young girl but was force to evade when dark violet sphere blasted into nearly grazing her face.
Meanwhile, Albion reach out then clench her fist to compressed part of the barrier then launch her own dragon flames towards the young girl. However, it only smiled then swipe her parasol dispelling the attack.
"Tsk I thought you had long been gone. You were still alive huh, old bitch."(Irene)
"I didn't expect for you to come and show yourself after countless years."(albion)
"Fufufu that's how you treat your mother?"
Everyone was shocked from her words. They couldn't believe if her words was true or not but the person had claim herself to be the mother of two Heavenly dragon. Irene and Albion bit their lips from frustration being around her. Both heavenly dragon were releasing an absurd amount of killing intent.
"Well it doesn't matter and for your information I was sealed for I don't know long but thankfully those dark apostle unsealed which is quite convenient. Now that you've grown I can finally devour you my daughters!"
"Irene what's going on!? Who is that girl!?"(Rossweise)
"She is one of the dragon god that been long forgotten and mother of the Heavenly Dragon. Gore Magala, True dragon goddess of the Void."(Great red)
"W-Wait why haven't we heard of her?" Rossweise)
"No one knows where she was or what happened but the only thing you need to know is that she's the strongest dragon god that even I can't hope to match."
"Shit we are in big trouble now!?"(Saji)
"You lot stay back. Let us handle her while you guys finish off the small fries."(Irene)
Upon saying her words, over a dozen of mass produced evil dragon was created behind the gothic Lolita who remain smiling at them. Rossweisse quickly assist by summon complex magic circle blasting them at the creature while Saji and the rest of Sona's peerage engage them in battle.
The Valkyrie summoned a staff that Issei gave that increased her magical spell by a thousand times. She used spatial magic to send the creature to the dimensional gap as using powerful elemental spell massive collateral damage.
She tried using it on the new arrival but the person vanish in a blink of an eye appearing near Irene who barely evade her sphere then used penetrate while boosting her strength managing to push her away enough as Albion appeared in the direction where the Lolita was sent then created small silver white ball.
"Divine Divider compression blast!"
It shot towards the gothic Lolita who smirk in delight as her long skirt morphs into enormous thin dragon arms that reach out to blocked the attack then it shattered the blast like nothing. Her appearance change with her left eyes visible as each limb had Dragonic armor along with headband that had pointed horns.
She used her new appendage to strike Albion who tried to blocked as it was too fast to evade. Upon impact her whole body remain in place for split seconding then was flung into the air. Afterwards, Gore Magala created ball of darkness blasting towards Albion who barely used her Dividing power to reduce it.
"You had grown my lovely daughters~"
She didn't even flinch when Irene created thousands of glowing red orb that blast barrages of laser beam. It was easily disburse by single swing of her extra appendage. Gore Magala then took deep breathe pumping her chest.
"True Dragon god…ROAAAARRR!!!!"
Irene immediately cast boost into a multilayered barrier around her as power black misty flames enveloped her whole body that was able shattered it then was met with Gore Magala palm as she was grabbed her face then appeared far away from anyone.
She was able to escaped by using a tier magic time stopped boosting it then remove her grasp and once Irene escaped she used penetrate while doing palms strike that was boosted by another million times.
Time resume resulting in Gore Magala coughing out blood as she was push back several meter away from Irene. Both took deep breath as they were tired from each others attack.
"H-Hahahaha you manage to wound me my precious daughter! Oh I wonder how you tast-"
Before she could finish her words, A her body move barely escape a vortex that reduce the area where she was into nothingness. It was circular radius that create a vacuum in small area a creating crater below.
"Triple maximized magic, White void!"
Then Gore Magala extra appendage was sucked both of them in a white vortex while her humanoid form barely escape the third one. She stared at the new arrival who sending silver white ball that reduce everything into nothing.
"Irene that look suit you better."(Albion)
"Piss off, bitch. I was just getting started."(Irene)
Stood up dusting off herself as both of them prepared for the incoming battle. Gore Magala face distorted becoming into a sadistic smile as her aura rose.
"Hahaha come my daughter let me see your progress!"
Upon her words everything became silent for split second that seem to be an eternity. However, instantly change when booming aura push everything back.
[BOOST!BOOST!BOOST!BOOST!BOOSST!]
[DIVIDE!DIVIDE!DIVIDE!IDIVIDE!DIVIDE!]
Irene boost herself for hundred millions while Albion used dividing power to steal some of the boost to increase her own. Their power skyrocketed allowing them to become stronger than the former dragon gods.
The two finish their power up and was instantly where Gore Magala prepared to black their attack with her newly regenerated appendage but it result in obliterating them shocking her. It shattered her barrier as both heavenly strike impact her body with Albion did downward swing of her fist while Irene punch her straight in the abdomen.
Gore Magala head exploded while her body destroyed from the sheer force of their attack. A massive mushroom cloud form as everything nearby was caught in the crossfire destroying hundred meter of land. Thankfully, Albion had used Powerful barrier before joining the battle ensuring no one would notice them though it had now shattered. Nonetheless, it had serve its purposed as the two heavenly dragon was exhausted due the fact that Gore Magala power was [Draining] that enable her to drain their power with full absorption.
"Haaaa…how annoying that you two manage to wound me this much."
Distances away was regenerating body of Gore Magala unaffected by the fact that her body was turn into dust. Albion and Irene click their touch in frustration as they were far to exhausted to fight. Gore Magala [Draining] was to strong for them. It wasn't because their weak but the ability is to broken.
"It's truly unfortunate that I can't get you today but I'll come back soon to visit my precious daughter."
"W-Where are you going!"(Irene)
"Hahaha don't assumed that I'll let myself be servant merely because they unseal me? No, I would rather work alone and enjoy this new world for myself. Well see you around~"
"Wait, don't let her esca-!"(Albion)
She tried to stopped Gore Magala to escaped but no avail as massive energy felt from the whole world even outside draconic deus. Albion and Irene looked at each other knowing who it is.