"The kingdom that you swore to protect... the people... the person important to you... I will not forgive someone like you, who betrayed everything he stood for!"
Cain Barzad「ケイン＝バルザド」 is a former Holy Knight of Danafor, having survived its destrucion as he was on a mission at the time. Disguised as an ordinary elderly man, he leads the Deadly Sins to Vaizel's annual fighting festival, which he also participates in personally.
Cain is a short elderly man with combed, grey hair, and a long mustache and beard. He also wears a clock, and his eyes seem to be always closed. Under his cloak, Cain wears trousers, and a long shirt that bears the crest of Danafor.
During his time as a Holy Knight, Cain wears a strange set of full body armor with an antler-horn helmet wielding a whip as shown in Meliodas' thoughts when he remembered him and in a flashback.
Cain appears to be a reserved but friendly, elderly man with a certain aura of mystery to him. Even after the destruction of Danafor he still remains loyal and proud of his kingdom, willing to stand for its ideals even in battle. He can also be very passionate and sensitive. He knows Meliodas from the past and, initially believing that Meliodas is responsible for its destruction, begrudges him and his actions and questions his morals and honor. However, he quickly makes up with Meliodas and is deeply moved once Meliodas ensures him he had nothing to do with the destruction of their kingdom.
Despite his old age, he displays youthful enthusiasm when he happily skips his feet while talking to Meliodas and greets Howzer and Taizoo with a "Yo".
Cain seems to originate from Danafor. In his time as a Holy Knight, Cain witnessed Meliodas sparing Liz from execution and taking her in. Cain and his fellow Holy Knights are against it but was surprised that the leader of Danafor's Holy Knights is willing to make his comrades enemies if they do not want Liz as one of them.
Later inside the castle, Cain saw Liz having a hard time trusting Meliodas as the latter groped her chest and the former attempting to smack him whilst removing his helmet. Eventually Cain and the rest of his comrades grew to like Liz and accepted her as one of their own. At some point of time, Cain received Liz' Sword after being told by Liz of Meliodas' reason of rejecting her gift.
After completing an unspecified mission, Cain returned to Danafor, only to find it destroyed by a great calamity and was deeply saddened by this. He remained loyal to the country which no longer exists as he traveled around Britannia. On his travels, he heard rumors that Meliodas is the one responsible of Danafor's destruction, which led to Cain's suspicion and doubt.
Cain is first seen in Vaizel when he drunkenly questions Meliodas and the others as to what they were looking for, since they did not seem to be merchants. When they answer that their objective is a weapon that "no one can use", he then leads them to Vaizel's annual fighting tournament, whose reward includes a gigantic warhammer which turns out to be Gideon, Diane's Sacred Treasure. Cain is then revealed to have also joined the tournament, an action he claims to have been in a "drunken spur of the moment", and to have survived the preliminaries, after which he is assigned to fight against King.
Later, after he enters the ring for his battle against King, he is shown to still be drunk, while the commentator speculates about the power the two fighters are hiding, having not participated actively during the preliminaries. However, both of them appear to be quite weak, much to the audience's disappointment. When King jogs toward Cain, intending to punch him in the face, believing to land a great hit, he greatly misses his target. Cain in turn readies a punch but only lightly knocks King in the head, an "attack", King comments, to have been very strong. King, feeling sort of outclassed by his opponents "strength", retreats and then uses his ability "Disaster" on Cain to trigger his rheumatism. Cain, feeling the effect immediately, is alarmed and lunges toward King with great speed. He delivers an elbow punch which blows the Deadly Sin out of the ring, stating that he was so surprised that he lost control of himself.
Sometime later, after Meliodas and Ban's battle has ended, Cain is shown to have carried Taizoo from the area where he landed following his defeat. Cain commends Taizoo for putting up a good fight, but the former mountain bandit retorts that it was certainly not so, and he had, from the beginning, known of the difference in his and Howzer's strengths, and of his opponent being a Holy Knight. As the current the battle between Diane and Howzer continues, Love Helm comments that Diane can only defend herself against Howzer's attacks. Taizoo compliments her for even doing that, adding that if she is caught within the twisters even a bit, she will be defeated, and that Howzer's attack was not something an ordinary human could withstand. Cain questions Taizoo whether he has had an unpleasant experience with a Holy Knight before; the latter admits to have had one with a Holy Knight from Danafor. Cain's reply makes it seem as though he knows of the now destroyed kingdom's fate.
After Howzer vs. Diane ends, and Cain's battle against Meliodas is declared, both fighters enter the ring. While both of them are being cheered on, Meliodas states that his having to fight the elderly man who gave him directions before is a coincidence, and also adds that Cain having defeated "Old Fart" did not seem like one. Cain replies that the world ran on "fortuity and necessity", and also that him entering the tournament was following a clear objective rather than coincidence. He also questions his opponent, having become certain after hearing the name, "Meliodafu", whether he is Meliodas' son. He is greatly bewildered and shocked when Meliodas answers that he is the man himself. Cain initially refuses to believe so, adding that if Meliodas were alive, he would be in his thirties.
Meliodas, stating that he did not know who his opponent was, therefore questions the relevance of Meliodas' identity for Cain. As Love Helm encourages them to finally commence their battle, Cain states that he found Meliodas' identity hard to believe. Before finishing his statement, he attacks his opponent repeatedly, all of which are blocked, and then jumps back. Removing his cloak and revealing a shirt with a symbol on it, Cain declares that he will not forgive someone like Meliodas, who betrayed the "kingdom he swore to protect", "the people", "the person most important to [him]", and "everything [he] stood for". Meliodas then recognizes the symbol on Cain's shirt, it is the crest of the Holy Knights of Danafor.
Cain creates a small fireball, and releasing it, questioning Meliodas for the reason he destroyed Danafor, with the latter not defending himself. Cain continues his attacks, all the while further questioning his opponent about the reasons he killed the people of Danafor, and Liz, and then releases a giant fireball. Meliodas finally replies that he had tried to protect them, but failed, and that this failure is his sin. Meliodas then uses a technique that completely disperses the attack, Cain immediately recognizes it as "Counter Vanish"; the use of this technique convinces him of Meliodas' identity. Meliodas replies that he has come to remember Cain as well, and reaffirms Cain of his earlier statement. Cain is happy that the rumors he heard about Meliodas' responsibility for the destruction of Danafor are false.
Glad to be rid of his suspicious, Cain forfeits the match when Love Helm interjects. While walking out of the ring, Cain asks his old friend why he never used "Full Counter" to deflect his fire attacks, only for the latter to explain that he would not survive the feedback of his attack if that ever happened. Cain walks away from the ring, and towards Howzer and Taizoo, greeting with a "Yo" and questioning them if they have more energy, which they confirm. Cain then witnesses Diane and Meliodas' battle, and, as the latter suddenly threatens to massacre the citizens of Vaizel if they do not leave the town, looks on in confusion. A commotion breaks out when suddenly Vaizel is attacked by a raining hail of explosions. The origin of the attack is Guila who has arrived with back-up in the form of Jericho and Marmas. Meliodas and his comrades get ready to fight while he and Ban scare off the last onlookers to save them from the ensuing carnage.
Cain somehow survive the destruction of Vaizel after helping the civilians evacuate the area, Cain later travel to Ordan where he found Boar Hat to have some drink since the other places are close. When Cain knock the door, Elizabeth Liones appear to welcome him, but Cain stood there in shock, thinking he was in a dream and then yelled out Liz, thinking Elizabeth is the latter from Meliodas past. Elizabeth let Cain in and offer him some drink while he talks about how much she look and feel like Liz. Elizabeth ask if she was his daughter but Cain said Liz was Meliodas' lover which made Elizabeth speechless. Cain talk about how Meliodas met and saved Liz, and she became closer to everyone in Danafor even Meliodas. Cain then mention that Meliodas was a simpleton to which Elizabeth said he is not a simpleton but really kind which made Elizabeth blush.
Cain then told Elizabeth the reason Meliodas never used a real sword and that Liz offer him a sword but regret it since he believe he would kill someone with a sword. Later Cain then sense a large power coming from the forest to which he told Elizabeth to stay behind, but encounter Diane who was shock to the latter being a giant. After the Sins return with their comrade Gowther returning to their ranks, Cain bade his farewell to Meliodas, but ask Meliodas if he were putting a image of Liz onto Elizabeth which Meliodas did not respond.
During his battle with King, Cain initially appears to be very weak, but when King starts using his ability, displays great speed and strength compared to a normal human, moving toward the Deadly Sin in an instant and punching him out of the ring. As a Holy Knight of Danafor, Cain might be powerful even in his old age. In his time as Danafor's Holy Knight, Cain had a whip which might be in conjunction of his ability "Blaze".
- Main article: Blaze
火炎Bureizu」: Cain possess an ability that allows him to create, control and release fire.
Cain and Meliodas were old friends back in their days as Danafor Holy Knights. Cain seem to held high respect for Meliodas, but at times seem unease with his choices as to let a enemy, Liz, free and for making a princess work as a waitress. Cain grow unease when the rumors of Meliodas destroying Danafor and went to the Vaizel Fight Festival to find out the truth. After Meliodas told Cain that he did not betray anyone, Cain was very happy and grow tears to know his friend did not betrayed them, and became friends with Meliodas again, as he search for him when Vaizel was destroyed to check if he was okay. Cain worried over Meliodas whether he was he is projecting Liz onto Elizabeth, worrying that Meliodas didn't move on with the latter not replying.
Cain at first sees Liz as the enemy of Danafor and was unease with Meliodas choice to set her free. But at times, he grew close to Liz and see her as a close comrades and grew sad to her death. Cain grew shock and speechless when he thought Liz came back to life, but was someone who looked like her. Cain said she had a gentle voice and aurora which draw him and the other Holy Knights, and said she would have been a beautiful woman by now if she had not died during the destruction of Danafor.
Cain and Elizabeth hold a good friendship, as the latter resemble Liz and at first thought Liz somehow came back to life. It is believed that Cain sees a lot of similar to Elizabeth to Liz despite the appearance.
- Cain, according to the Book of Genesis, is the elder of the two sons of Adam and Eve, who committed the first murder by killing his younger brother, Abel.
- Cain is one of two people whom Meliodas did not recognize due to their armor, the other being Gowther.