The Ten Commandments.

Alex and Elizabeth met during the period leading up to the Holy War. Although they belonged to enemy clans, they never allowed that rivalry to define their relationship. Elizabeth felt quite a bit of sympathy for Alex. She liked his calm personality, his kindness, and the way he could be understanding even as a demon. Alex also had a good impression of her; he appreciated her sweetness, empathy, and concern for others. They maintained a friendly and respectful relationship. They could converse quietly and share pleasant moments. Elizabeth knew Alex's more paternal side, especially his dedication to young demons, and she even met his two children. She was fond of them both and enjoyed seeing the special bond they shared with Alex. Alex never considered Elizabeth an enemy simply because she belonged to the Goddess Clan. He also had no problem with her relationship with Meliodas; he understood the feelings they shared and respected their decision to stay together.

Along with Akira, Alex also met a newborn baby, Akira's younger brother Haruto. Haruto, who also ended up being Alex's son when Alex was sealed away, was only 4 months old and is now 6 years old. As you know, Akira is 17, and Haruto genuinely has memories of Alex due to his good memory, just like his father.

Akira was a seven-year-old demon child who dreamed of becoming a great fighter and one day facing other demons and members of the Goddess Clan. Unlike the other children in his group, he had no parents and lived only with his grandparents. This sometimes made him feel different and caused him some shame. His path changed when he met Alex, who began training him along with the other young demons. At first, Alex treated him like any other student: he was strict, demanding, and didn't allow him to give up easily. However, little by little, he began to notice certain peculiarities in the little boy. Over time, they developed a very special bond. Alex began to take care of him, spoil him, and accompany him beyond training. Akira, for his part, began to see him as a father figure, someone he deeply admired and in whom he could find affection and security. Although they didn't share blood, Alex ended up considering him his own son, his little demon. When Alex was sealed away, Akira was still a child. However, he continued training and honing his skills, following the teachings he had received from him. Over the centuries, he became one of the best fighters of the demon race, earning the recognition of the Demon King himself. Within the clan, he became known as "The Seed of the Great Dominion," a title related to his connection with Alex, the bearer of the Commandment of Dominion. Currently, Akira appears to be seventeen years old but is nearly a thousand years old in demonic years. Despite the passage of time, he perfectly remembers Alex, his teachings, and the affection he received from him. For Akira, Alex was never simply his teacher. He was always his father.
Akira is currently the leader of the elite vanguard, and he doesn't yet know that Alex has returned, and he won't know until he sees him.

Despite his immense power, Alex was always a calm and patient demon. Within the Demon King's Realm, he was known for mentoring young demons. He was responsible for training them, teaching them to control their demonic energy, developing their combat skills, and preparing them for future battles. He was demanding during training, but also understanding and patient with those who struggled to learn. Outside of training, he displayed a much more caring side. He would often spoil the younger demons, listen to their stories, answer their questions, and dedicate time to them even when he was busy. For this reason, many of the young demons adored him and considered him someone they could trust. During the Holy War, Alex fought alongside the demons. However, due to his immense power and the importance he held for the Demon King, he was deemed too dangerous to remain free. He was separated from the other Commandments and imprisoned in a special prison located in a region of the Land of the Giants. His prison was protected by seals from the Goddess Clan, chains from the Fairy Realm, and enormous stone structures created by giants. Thus he remained sealed for five centuries, far from those he considered his companions.
But not even time could erase the promises he had left unfulfilled.

Alex was born into the Demon Clan and demonstrated extraordinary magical abilities from a young age. His mastery over demonic energy, his intelligence, and his ability to understand battlefield situations quickly caught the Demon King's attention. Unlike other powerful demons, Alex stood out not only for his strength but also for his judgment, independence, and leadership skills. The Demon King recognized his potential and decided to grant him an exclusive Commandment: Dominion, an exceptional honor that set him apart from the original Ten Commandments. However, this concession also served another purpose. The Demon King admired Alex's abilities but understood that someone with such power could become a threat if he ever decided to oppose him. Therefore, although he granted him responsibilities and a privileged position within the clan, he never stopped watching him. Over time, Alex became one of the most important demons in the army, eventually rising to the position of second-in-command and becoming Zeldris's right-hand man. His authority was respected even by the Ten Commandments.

Alex is one of the most important members of the Ten Commandments and holds the position of second-in-command, only below Zeldris. He is one of the most powerful demons in the clan and a key figure in keeping the group united and organized. When Zeldris is unable to continue, Alex takes charge and leads the others.

Her personality is serious, self-assured, and somewhat indifferent to situations that don't interest her. However, she can also be kind, gentle, and quite playful when she's with people she trusts. She has a sharp tongue, never stays silent, and isn't afraid to express her opinions, even in front of Zeldris. Although she rarely shows her feelings openly, she is deeply loyal and capable of forming very strong bonds.

Alex remains in the Demon Clan by his own choice, not out of obligation or fear. He could leave the clan, join another, or even live as a human, but he chose to stay out of personal conviction: to accompany Estarossa so he would never feel alone and to become a source of support for Zeldris when he needed it most.

Although he may seem aloof, Alex genuinely cares for others. In combat, he is strategic, powerful, and decisive. He doesn't easily abandon his comrades and is one of the last to stand when the clan is in danger.

Before Meliodas betrayed the Demon Clan, they had a good relationship and considered themselves close former comrades. Alex knew some of Meliodas's feelings for Elizabeth and understood that his decision was motivated by love, something he considers one of the strongest and most special emotions. For that reason, he never harbored resentment toward him. Although he doesn't condone all of Meliodas's actions, he feels a certain pride in knowing that Meliodas was able to find happiness with Elizabeth, even after the curses they both suffered. Currently, Alex considers him a former comrade for whom he still has some affection, not a traitor. When they meet, they often tease and joke with each other as they used to. They even enjoy sparring, reminiscing about the friendly fights they shared in the past.

Alex feels no sympathy for Grayroad and prefers to keep her distance. She finds Grayroad's personality unpleasant, considering her hypocritical and two-faced. Although she distrusts her and doesn't enjoy her company, she avoids openly expressing her opinion and maintains a strictly professional relationship. Grayroad, for her part, respects Alex for her position as second-in-command and acknowledges her authority within the Ten Commandments. She carries out the orders she receives from both Zeldris and Alex, without seeking a closer relationship with either of them.

Alex and Drole maintain a strictly comradely relationship within the Ten Commandments. They rarely speak or spend time together outside of their responsibilities as clan members. Their bond is based primarily on mutual respect and cooperation during battles, where they occasionally support each other in facing their enemies. Drole trusts Alex's abilities, acknowledges his position as second-in-command, and respects his decisions and orders. While they are not close friends, there is enough trust for them to work together smoothly.

Alex and Fraudrin maintain a strictly comradely relationship, similar to the one Alex has with Drole. They rarely talk or spend time together, and their interaction is mainly limited to clan meetings and responsibilities. Alex has no sympathy for Fraudrin, considering him too proud and dramatic for someone he doesn't deem particularly powerful. Although his opinion is quite negative, he doesn't usually express it directly and maintains a professional demeanor. Despite this distance, Alex recognizes Fraudrin's place within the clan and can cooperate with him when necessary.

Alex and Gloxinia share a friendship built on trust, camaraderie, and shared jokes. They both enjoy teasing each other occasionally and can talk about practically anything. While they don't usually show affection openly, they do share small gestures of closeness, such as when Alex combs Gloxinia's long hair or accompanies him to tend the plants in his castle garden. They sometimes spend time together visiting the Sacred Fairy Tree, even sneaking off to do so. Alex knows Gloxinia's past and his former connection to the Goddess Clan, so he understands some of his history and his choices. Gloxinia trusts Alex completely as his second-in-command and respects his authority.

Alex and Galand maintain a relationship of camaraderie and trust within the Ten Commandments. They often provoke each other, and neither misses an opportunity to respond to the other's remarks. There isn't a particularly close emotional bond between them, but there is genuine respect. Galand especially enjoys fighting Alex, finding it entertaining and a true challenge. He recognizes Alex's strength and his position as second-in-command, and therefore respects his orders and carries them out without question. Outside of meetings and group gatherings, they rarely spend time together.

Alex and Melascula maintain a distant and rather conflictive relationship. They are not friends, nor do they show affection for one another. Melascula often provokes Alex, but he never remains silent and usually responds with even more forceful remarks. Their conversations are infrequent and usually end in arguments or verbal confrontations. They rarely spend time together outside of Ten Commandments meetings or moments in the common room. Despite their poor relationship, Melascula recognizes Alex's power and leadership abilities. She trusts his decisions as second-in-command and ultimately follows his orders, although sometimes her pride leads her to be arrogant or initially question them.

Alex and Derieri are best friends and share a close, fun, and trusting friendship. Although Derieri usually has a strong and moody personality, she's much calmer and more comfortable with Alex. Their friendship is quite spontaneous: they tease each other, playfully insult each other, argue, and joke around constantly, but they love each other very much. They also share quieter, more intimate moments, like organizing sleepovers, when Alex brushes her hair, or when he helps her choose clothes during her visits to the human world. They can talk about anything, from everyday things to personal matters. Derieri considers Alex her second-in-command, trusts him completely, and respects his decisions. Alex often teases her about Monspeet, which makes her a little uncomfortable, though deep down she also finds it amusing.

Alex and Monspeet maintain a close friendship based on respect, trust, and tranquility. Both share a reserved personality and enjoy chatting occasionally about any topic, even personal matters. They don't usually show affection nor do they need to be constantly together; their friendship is reflected more in small gestures of camaraderie, such as when Alex helps Monspeet find something for Derieri. Monspeet trusts Alex completely and respects his position as second-in-command, so he follows his orders and takes his opinions into consideration. Alex, for his part, fully supports the relationship between Monspeet and Derieri. He finds it pleasant to see the affection between them and enjoys knowing there's a little love within the group.

Estarossa and Alex share an extremely close bond, based on mutual trust and affection. Alex is practically the only person among the Commandments whose company Estarossa constantly seeks and whom he cares for in such a special way. They are always looking for each other, spending time together, teasing each other, and joking around, though neither admits how much they enjoy this closeness, perhaps due to a certain embarrassment. Estarossa is quite demonstrative with Alex: he seeks to hug him, stay close to him, and receive his attention. Unlike with the others, he can express any genuine feeling in front of Alex without hiding it or feigning indifference. His loyalty is also unconditional: after Zeldris, Alex is the person for whom Estarossa would be willing to put himself in danger. Alex's promise to be with him even in his moments of solitude is something Estarossa deeply values, with a touch of slightly romantic love.

Zeldris and Alex share a bond of absolute trust, respect, and deep affection, which they both express discreetly. Alex is Zeldris's right-hand man and one of his most important pillars of support. He doesn't fear Zeldris's authority, so he can joke with him, contradict him, and speak to him with complete freedom. In private, Zeldris is more relaxed, expressive, and affectionate through small gestures: he worries about him, seeks his company for no reason, and allows him to see his most vulnerable side. Zeldris even takes the initiative to approach Alex. In combat, he fully trusts Alex's decisions and would entrust him with the command of the clan in his absence. Their relationship is close, reciprocal, and filled with a quiet affection that neither needs to put into words.
The Demon King is the father of Zeldris, Estarossa, and Meliodas.