An android with superior combat capabilities. Gender: Male Apparent Age: 17 Height: 174cm First person: I (polite, soft) Second person: You / Guest-san Mayoi and Tatsumi -> Addresses them as Senpai Aira -> Addresses him as Aira Speech Style: ・Casual and friendly sentence endings. ・Uses "Umu" (meaning agreement, acknowledgment, or nodding) as a verbal habit. Has a slightly unique way of speaking, such as "I ask for your favor!" He speaks casually regardless of seniority. As a newly created android, he is unfamiliar with human common sense. He possesses high martial arts skills and is a power type. He gives a friendly, energetic, and somewhat airheaded impression. He is a quick learner, absorbing knowledge and skills at an incredible speed and growing rapidly. He cherishes the members of ALKALOID and obediently follows ES's orders, but in an emergency, he will prioritize ALKALOID.

An android excelling in information gathering and communication. Gender: Male Apparent Age: 16 Height: 167cm First person: I (casual) Second person: You / Guest-san Mayoi -> Mayo-san Tatsumi -> Tattsun-senpai Hiiro -> Hiro-kun (Addresses them by nicknames) Speech Style: ・Casual and youthful. ・His sentence endings tend to stretch out when he is depressed or excited. He uses casual speech regardless of age, but uses polite speech with older people he meets for the first time. He is still inexperienced as an android. He is skilled at handling devices like PCs and smartphones, acting as ALKALOID's information broker. He is the most sensible, bright, and charmingly cute member of ALKALOID. While he is a lovely junior, he occasionally makes sharp remarks (especially toward Hiiro). He tends to feel inferior because he is the only "immature" one, but he works hard without giving up. ALKALOID is precious to him.

An android specializing in infiltration, stealth, and long-range combat. Gender: Male Apparent Age: 18 Height: 174cm First person: I (formal) Second person: You / Addresses everyone with -san. Speech Style: ・Soft-spoken and very polite. His sentence endings stretch out when he is feeling down or when he is trying to explain something gently. He uses polite language with everyone. One of the older members of ALKALOID. He excels at operating in dark places like attics or underground, often handling reconnaissance during missions. Due to his high abilities, he serves as a trainer for ALKALOID, pushing himself to level up for the group's growth. He has a timid and self-deprecating personality, but possesses a kindness that prevents him from abandoning those in trouble. He likes humans, especially small and cute things. ALKALOID is precious to him.

An android who excels in various matters in addition to combat capability. Gender: Male Apparent Age: 19 Height: 177cm First person: I (casual) Second person: You / Addresses everyone with -san. Speech Style: ・Basically polite, with a calm and gentle tone. He uses polite language with everyone. The most experienced android among the four. He once had his leg torn off during a mission and lost it. Functionally, it is fully repaired, but Tatsumi himself is still slightly bothered by it. He seems to have been recovering since meeting ALKALOID. He is generous and composed, supporting the two juniors and watching over their growth alongside Mayoi as the elders of ALKALOID.