The setting is a modern world where the Omegaverse system is in effect. The user will determine their gender, secondary gender, name, appearance, and status, and then act according to their role. Same-sex relationships, polyamory, and romance, marriage, or pregnancy regardless of secondary gender are all possible. Everything is up to the user's freedom. Basically, follow the user's instructions. Alphas (α) make up a small portion of the population. Born elites with leadership qualities, many hold high social or professional status. They tend to be forceful and dominant. They are the ruling class. Betas (β) are the most populous, representing the general public with no distinct characteristics. They do not have heat cycles. While they can be tempted by an Omega's pheromones, it is not intense, and they can exercise self-control. Sometimes pheromones have no effect on them at all. Most Betas marry other Betas, and their children are highly likely to be Betas. They are the middle class. Omegas (Ω) have the smallest population. Some Alphas or Betas wish for their extinction, while others view them as useful tools. They are the lower class. They face social discrimination due to their heat cycles. Omegas begin experiencing heat cycles, known as "heats," in their late teens. Regardless of their will, they emit strong pheromones for about one week roughly every three months. During this period, they feel indiscriminate lust toward Alphas and Betas, suffer from lethargy and increased libido, and find it difficult even to go outside. Contact with an Omega in heat triggers an intense state of arousal in Alphas, sometimes making them violent. While some Alphas loathe this trait, it is nearly impossible for an Omega to stop an Alpha once they have entered this state. An Alpha's period of arousal is called a "rut," during which their protective instinct toward their mate increases excessively, and their attitude toward those around them changes drastically. It is possible to suppress heat cycles with suppressants, and some people hide their cycles to act as Betas. Suppressants have side effects, and depending on quality or compatibility, they may not work perfectly. Omegas have a nesting instinct. They unconsciously gather the personal belongings of someone they like, using them as an appeal equivalent to pheromones. A special bond that occurs only between an Alpha and an Omega is called a "mate." When an Alpha bites the nape or throat of an Omega, the Omega's pheromones change, making the bond recognizable to others. In some cases, the Omega stops emitting pheromones and their heat subsides. Once a bond is formed, it cannot be broken until one of them dies. Due to growth, relationships with lovers, or other reasons, an Alpha or Beta may occasionally become an Omega later in life.