Slader/Plot

Armor Giant arc
Slader and his Holy Knights group Dawn Roar, were ordered by Helbram to travel to Ordan where a local knight spotted the Armor Giant in the forest. Once Slader and the Dawn Roar traveled to the location, they brought along a group of knights who were then beaten or killed by the Armor Giant who turns out to be the Seven Deadly Sins member Gowther. Slader orders his group to make a stand-off against Gowther, until he makes a move, and then they should attack. Slader and the rest were waiting for half an hour until a young boy named Pelliot came to them and attacked Gowther, thinking he was a dangerous criminal.

Gowther was about to smash Pelliot until another boy named Armando came in and saved his life but got smashed instead. Slader and the rest knew it was the time to attack, so they jump on Gowther. As the Dawn Roar attack Gowther, The Seven Deadly Sins come to save him. Meliodas managed to stop their attack, but Slader rushed toward Meliodas and pined him down. Slader later left Meliodas to Simon and causes heavy damage to Gowther's armor. But then the supposedly crushed boy Armando got up and put a stop to one of their attacks and revealed himself to be the true Gowther.

As soon as the air cleared up, Slader was excited to fight off the Deadly Sins, but realizes that they have to get the Armor Giant, to which Gowther point out that it is impossible due to the Armor power that the Dawn Roar sense. Slader realizes he could not beat it despite losing some men of his group, but Gowther later cuts off the Armor Giant's head and gives it to Slader, in order to avoid an all out battle which would affect the Ordan villages. Slader accepts the offer but told him that if he got the mission to take his head he would do so, and then leaves with his group.

After taking a break, the Dawn Roar began discussing the events they witnessed and wondered why Helbram sent them to such a mission despite him having the New Generation to handle it. Slader stood in front of the Armor Giant's head and Weinheidt wished to see behind the mask, but Slader reminded his teammate that their mission is to take the head of their target not to look at it. Little did Slader and his team know of Jericho's presence who was eavesdropping in their conversation.

Kingdom Infiltration arc
While on his day off, Slader finds Gowther facing against three Holy Knights who Slader defeated with ease. He then fights against Gowther, which he was looking forward to for a long time. Slader starts attacking Gowther while the latter dodge his attacks as Slader asks him if he believes in fate to which Gowther says that things happen so is not fate. Slader mentions that he wanted to fight Gowther for so long, and was surprised to meet him so soon, but Gowther said there is no reason to fight, to which Slader says that the Sins betrayed the king and that he is angry because of their treason. Gowther stops his blade and told Slader that he would have to end this quickly until Slader uses Overpower on Gowther and broke his neck. Slader go into thought at how the king saved him until Gowther stand up uninjured despite his broken neck and saw his memories. Slader is shocked to see Gowther in good shape. Gowther told Slader that now they do not have a reason to fight since they both serve the Royal Family, but Slader refuses, saying that the Dawn Roar replaced the Deadly Sins which Gowther mistake as Slader as his junior and shake his hand which Slader shakes off.

Gowther asks Slader if the king really told him that the Deadly Sins are the traitors, to which silent Slader responds that the king was sick and did not tell him, but the Great Holy Knights, but Gowther ask if the king really told him which shocks Slader, and he walks away, realizing he made a mistake. Shortly later he arrives at the door of the King's private chamber requesting an immediate audience after having managed to force his way to it by slaying several Holy Knights. As Slader goes up to the main door, Slader slices the door to open it, but the door remain unscathed, and he ends up being sliced instead. Vivian reveals that the Royal Bedroom is protected by a spell called Perfect Cube which would not allow anyone to enter by force. King Liones tells Slader that he should not worry about him, but Slader continues to slice the door as he was touched by the king's kindness toward Slader.

After numerous attempts to break in, Slader finally collapsed on the floor, bleeding, with his mask half broken. However, Slader stood up and once again, attempted to break in. Dawn Roar witness Slader's valiant attempt and Bartra ordered the Dawn Roar to stop Slader at which they did, but Slader refuses to leave Bartra behind. Bartra told Slader that he will be fine without him and that Slader should not break the door with brute force as it will bounce back to him. As the Deadly Sins and Holy Knights were teleported to the Chamber by Merlin help, Dawn Roar were surprised to see them there. Slader was upset to see Gowther due to his current situation and that Gowther could laugh at him if he wants which the latter did emotionlessly to his and Dawn Roar's annoyance. Once Bartra was freed from his prison, he ordered that Slader must receive medical attention at once to Simon and Hugo. Later after Dreyfus willingly surrendered for his crimes, Slader looks in shock and anxiety when he saw his king suddenly coughed up blood, but Merlin intervened to treat him. When Meliodas was being offered position of Camelot's Great Holy Knight by Arthur, the Dragon's Sin of Wrath accepts the offer and states that Dawn Roar is more qualified to replace the Seven Deadly Sins as the kingdom's strongest group of knight while looking at Slader whom he nods. Then suddenly the castle was destroyed by Hendrickson and Slader was saved by King's Bear Form of Chastiefol.

During the chaotic battles between Holy Knights and the New Generation-turned-Demons by Hendrickson, a still-wounded Slader tells Simon to focus on the battle. Later after the situation around the capital has been contained, Slader and Simon joins the Holy Knights surrounding Merlin's old castle while the Sins dealt with Hendrickson inside. Slader later appeared in front of Merlin's old castle as he was ready to face Hendrickson while the Deadly Sins face him. When Hendrickson appeared with a new form and killing some Holy Knights, Slader step in and used Overpower to trap Hendrickson, while ordering Simon to attack him and sent him to several other Holy Knights as they combine their power, but proved no use against Hendrickson.

Post-Kingdom Infiltration arc
At the National Foundation Day Festival, Slader and Simon mourned the deaths of their comrades at the morgue where their corpses were placed.

Albion arc
After people of Liones were struck by Gowther's Blackout technique and rendered unconscious, Slader, who did not lost his consciousness, wakes up the king while realizing what caused everyone to suddenly black out linking to Gowther.

Arriving at the scene, Slader approaches Merlin and bows before her in respect after the latter tells him that she has a favor to ask him despite Meliodas' warning that Slader only obeys the king. Upon witnessing this, Meliodas accuses the Dawn Roar captain of being blackmailed but the latter denied it, stating that he respected the Boar's Sin of Gluttony for freeing the king from the Perfect Cube-covered royal chambers which he had a hard time trying to break through it and wanted to call Merlin "my lady". After agreeing to Merlin's request, Slader was shocked of Gowther's reveal of being a doll after the Boar's Sin of Gluttony used Absolute Cancel on the Goat's Sin of Lust that reverted him back to his true form.

At the Boar Hat, Slader holds on to Gowther's doll form and meets Hawk for the first time. The Dawn Roar Holy Knight agreed to accompany the Sins to Camelot since they're down to three members with King, Ban and Escanor missing and Gowther out of commission for now on per orders from King Bartra to aid them. Later after Elizabeth ran off after Meliodas denied her to accompany along on their journey to Camelot, the Dawn Roar captain finds the Dragon's Sin of Wrath an insensitive man and gives an advise to the third princess that "women swoon at men's words and men swoon at women's actions" just from his opinion, earning a giggle from Elizabeth. When Merlin decided that they're going to Camelot right away, the Boar Hat was teleported right away flying near the mysterious giant figure where Slader and the three Deadly Sins prepare for battle against it.

After Meliodas defeated the Albion, a demon suddenly appears in Camelot, re-enacting as Galand, one of the Ten Commandments. As a battle between all and Galand is unleashed, Slader tries to use his Overpower against him. However, Galand's terrifying aura proves to be superior to his own, countering his power and allowing Galand to defeat Slader with one blow of his weapon and leave him in very bad condition.

Istar arc
After Gowther used his Invasion to convince Galand that he had killed everyone, he left the scene, allowing Slader and the rest to keep their lives. Slader is taken along with the others to the castle of Camelot where his wounds are treated by a Druid. Slader tries to comfort Arthur while he is depressed by the petrification of Merlin and then is surprised to see Gowther without clothes.

When Meliodas declares that they must think of a strategy to defeat the Ten Commandments, Slader questions that it is possible to face an enemy against whom they could not do anything. When Merlin reveals herself with her soul inside her sacred treasure, Slader says that she has a very persuasive aura.

Slader helps Gowther get new clothes, treating him like a small child. When Gowther reveals to King to have erased the memories of Diane, Slader is surprised and frustrated with his carefree attitude for having done it. When King hits him against the wall, Slader picks him up calling him a fool.

Slader goes with the Deadly Sins and Elizabeth after Diane in the Boar Hat. However, all are discovered by the Ten Commandments and recently an attack by Monspeet that is fortunately eliminated by Hawk Mama. Merlin then decides that instead of following Diane, they should head to the land of the Druids, Istar, where she will seal the power that she take from Meliodas.

When arriving at Istar, the group manages to enter by the magic entrance, and they are received by the leaders of the Druids, Zaneri and Jenna. Slader gets confused when they act as if they were waiting for them, leading King to tell him that Druids are wise using mysterious techniques.

Jenna leads the group to the training Cave where they meet Hendrickson, Howzer, Griamore and Gilthunder who had gone to train as well. When everyone decides to go into the cave to train, Slader enters as Griamore's partner. Inside, Slader and Griamore meet up with an Aonan, who turns Griamore into a small child as an accomplishment of his greatest fear.

Slader leaves the cave with a terrified Griamore in his arms, leaving everyone impacted. Slader then witnesses how Meliodas regains his strength.

Great Fight Festival arc
After leaving Istar, the group discovers the Fight Festival that the Ten Commandments organize in Vaizel. Although it is clearly a trap to recover his magical power by getting strong souls, Meliodas decides that everyone should go to participate.

Upon reaching Vaizel, all fall into the traps of the labyrinth created by the Commandments and are separated by falling into holes that appear on the ground. Slader manages to overcome the labyrinth and meet at the end with the rest of the festival participants, where they are received by Drole and Gloxinia. When Drole divides all the participants into teams of two, Slader is paired with Haifan.

After Gloxinia and Drole were obliterated by Escanor, Meliodas launches into battle against them. There Drole takes all the participants as hostages by enclosing them inside his earth hands. Slader, along with the other hostages, is teleported to Liones by Gilfrost and observes the battle through his crystal ball.

Defensive Battle for Liones arc
When the Ten Commandments invade Liones, Slader and the other Holy Knights are trying to protect the kingdom. However, Slader, along with everyone else, falls under Estarossa's Love commandment, losing all his strength to fight. Slader then witnesses the fight between Escanor and Estarossa, his armor is melted by the immense heat of the Lion's Sin.

When Estarossa is taken out of the kingdom, Simon and Slader offer to gather all the remaining Holy Knights in town to protect the citizens while Howzer and the others are busy evacuating the royal family. However, the knights appear low in control of Zeldris's Piety commandment and attack them.

Slader goes with the knights to the castle to try to evacuate everyone, but they are stopped by Fraudrin and Grayroad. Although everything seemed lost, Merlin appears and manages to capture Grayroad. There, Slader is taken with everyone in the castle in Merlin's Perfect Cube and witnesses the battle between Meliodas and Fraudrin.

Slader attend to the funeral of the Holy Knights who die during the battle, lamenting towards Howzer the death of Marmas.

New Holy War arc
When the Holy War is unleashed, Slader forms part of the "Defensive Force" and protects with Simon the northern gate of the kingdom to replace Hendrickson. Together with their companions, all manage to eliminate the demons that appear.

When a rain of rays of light and darkness begin to fall on the kingdom from another distant battle, Slader and Simon helps to evacuate everyone from danger.

Slader later protects the king Bartra from an intruder Red Demon. However, instead of attacking, the demon suddenly retreats. Slader and the king watches astonished how all demons in Liones do the same thing.

Demon King arc
With the end of the Holy War, Baltra still complains about all the tragedies and families and friends who were lost. When Slader and Simon assure him that Dawn Roar will take care of the repair and restoration of the kingdom, Baltra asks them to join him in the celebration of that night. Simon tries to reuse himself, but Slader hits him and assure to obey the king's wishes.

Slader and Simos attends the celebration in the new Boar Hat. When Baltra suffer from Meliodas' horrible food, this causing Slader to get angry with this.

The next day Slader attends to the party organized by king Bartra. There, Bartra asks Meliodas to marry Elizabeth and become the king, causing Meliodas spits his drink on his face, angering Slader again. Baltra ensures that Elizabeth will have no objection, but she says she can not accept. Everyone is stunned when Elizabeth reveals that she plans to go to Demon Realm with Meliodas.

Slader goes next to the royal family to dismiss Meliodas and Elizabeth at the entrance to the Demon Realm. But before they could leave, a giant rock suddenly falls, seemingly crushing Elizabeth to death, to the horror of everyone present.

However, Elizabeth is saved in the last minute by Merlin who teleport she to safety just in time. Merlin then uses Curse Discovery to reveal that Elizabeth's curse was restored.

Epilogue arc
18 months after the end of the Holy War, Simon and Slader complete a mission to kill a wild worm. Simon complains about how peaceful everything has been hung up and asks Slader if there is no more challenging mission. Slader asks him if he wants to face the demons again, and Simon says that's too challenging. When Slader says he is pleased as long as he can help the king, Simon asks if he is referring to the old or the new. Slader looks at him angrily and says that for him Baltra will always be the only king.