Seven Deadly Sins & Four Archangels vs. Zeldris & Original Demon is a battle between the Seven Deadly Sins, along with two of the Four Archangels and Elizabeth Liones against Zeldris and the Original Demon.
After Zeldris, Chandler and Cusack recover from his previous defeat, the two high-ranking demons decides, in fact that Escanor and Merlin are too troublesome enemies and to let Zeldris to save his power to fight the Seven Deadly Sins, to fuse into their original form, the Original Demon. Their fusion dispel the field of darkness created by Meliodas and the Commandments, taking the battle outside the castle.
The Original Demon starts a fierce fight against Escanor. When Escanor receives a big slash in his chest after their clash, Original Demon mocks him for still being inferior despite Escanor being at his peak. Escanor then uses Cruel Sun, but the Original Demon blocks it with his shield. He rebuffs Escanor's claims of him and Merlin being enough, claiming that their deaths are already decided and no one could come fast enough to save them. Merlin then attacks him with Exterminate Ray, but the Original Demon easily overpowers and severely injures her with his energy breath and then gives Escanor serious damage with a kick of his back legs. However, before he can finish Escanor, Original Demon senses that something is coming. An enormous flying object comes to the scene, revealed to be King's Chastiefol, that the Original Demon barely managed to react to.
Original Demon is able to block Chastiefol with his shield and cut its blade with his swords. King then changes Chastiefol into Sunflower, releasing a massive explosion over the battlefield. Merlin is able to teleport herself and Escanor in time. However, Zeldris protects the Original Demon cancelling the attack with God and tells him to focus on Escanor and Merlin while he faces King.
Zeldris deals with Chastiefol True Increase and tells the distant King that he can not defeat him and that all of that is useless resistance. However, King changes Chastiefol into True Guardian and manages to hurt Zeldris with several physical blows. Zeldris then reveals to the Sins that they are not the only ones reaching Camelot since the Commandments that Mael have expelled are coming to rejoin with the others. As the four Commandments approach, Melascula's one react to them, leaving her body on his own to join them. The demons claims for the birth of a new Demon King.
Merlin refuses to give up and prepares to use Chrono Coffin, which both Zeldris and Original Demon recognizes with disbelief as the forbidden art capable of suspending time. The two are preparing to take down Merlin before she completes the spell and leaves the cocoon suspended in time. However, Zeldris is stoped by Chastiefol and the Original Demon is intercepted by Escanor, who are preparing to protect Merlin, who needs ten minutes to complete the spell. However, with Escanor now weakened, the Original Demon easily gains the upper hand and brutally injures him before he uses Death Drive to give the final blow, sending Escanor flying a great distance. However, before he could kill Merlin, Original Demon is restrained by Ludociel who uses Ark to stop his attack.
As Ludociel manages to contain all his attacks, the Original Demon receives great damage from his Lightning Spree. the Original Demon responds with Hellblaze Omega, but Ludociel easily undoes his attack and hits it with Sparking Drive. The Demon launches another Hellblaze Omega that this time gives more work to Ludociel to contain. With a smile, Original Demon receives several attacks from Ark and then launches a third Hellblaze Omega that manages to push back Ludociel. The body of Original Demon begins to break apart, leading him to reveal his true power Crisis that makes him stronger as his life runs out. He explains that by going against his punishment and returning to his original form, his flesh and bone is approaching its imminent destruction. In launching himself against Ludociel, he claims that he is pleased to sacrifice his life for the birth of the new Demon King.
There, the darkness that had been invoked over Camelot is eliminated by a great power of light, revealing to be Mael who arrives accompanied by the Seven Deadly Sins and Elizabeth. After hearing Mael try to dissuade Zeldris from making Meliodas the Demon King, a part of Cusack's conscience tells the Original Demon that they should not let that happen either. Ignoring him, the Original Demon charge against Mael, who uses Greatest Sun to catch him in a fiery explosion.
Zeldris protects himself with God, reminding him that no magical attack has an effect on him. In response to his previous request, Zeldris uses his darkness to attack Merlin, overcoming Ludociel's Ark barrier by dividing it into small dark creatures. However, Elizabeth and the Seven Deadly Sins manage to protect Merlin, who has five minutes yet to complete the Chrono Coffin.
Mael manages to catch Zeldris' arm and throw him to the ground with a spin. Zeldris then releases Ominous Nebula, attracting Mael with his vacuum. However, before he can attack, Zeldris' sword melts by Mael's Sunshine.
Mael and Zeldris engage in hand to hand combat, in which Mael manages to take the lead when damages Zeldris with Helios Fair. Mael there tries to ends the fight peacefully reclaiming that even under false memories, they used to be brothers and that they can come to an understanding by talking. As Zeldris states that Estarossa would laugh of hear that and rebuild his sword with darkness, Mael fights him again with two ark blades on his hands, overcoming Zeldris again. As the Chrono Coffin it is only three minutes from completion, Mael points that he is panicking, unlike his cold and stoic self. He asks if he wants to win the Holy War until the point of left his only brother to become something like the Demon King. As Zeldris appears at his back and slashes him with his blades, Mael cannot understand from where comes his desperate blood-curdling. Zeldris claims that Meliodas wants to be the Demon King and that he must be outside his way. Zeldris then manages to cut Mael leaving him on the floor and attacks the Sins with his darkness.
With just one minute left, Zeldris tries to stop Merlin, but his attacks are blocked by King's Pollen Garden who states that he can no longer win. Even so, Zeldris continues his desperate barrage of attacks but Mael appears and slash him in the back. As he can barely stand, Zeldris remembers Meliodas' promise of reviving Gelda after becoming the Demon King. As Chrono Coffin is completed and the cocoon is suspended in time, Zeldris finally falls to the ground saying Gelda's name.
While everyone are celebrating the apparent end of the Holy War, there is revealed that Meliodas have emerged from the cocoon before it was suspended in time. With a new and aged body, Meliodas appears now possessed by the Demon King.