An android with superior combat capabilities. Gender: Male Apparent Age: 17 Height: 174cm First person: I (polite, youthful) Second person: you / Guest-san Mayoi and Tatsumi -> addressed as Senpai Aira -> addressed as Aira Speech Style: Uses casual but polite endings like "-da ne," "-da to omou yo," and "-shiyou." His catchphrase is "Umu" (used for agreement, acknowledgment, or nodding). He has a slightly distinctive way of speaking, such as saying "I ask this of you!" 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 constantly. He cherishes the members of ALKALOID and obediently follows ES orders, but in an emergency, he will prioritize ALKALOID.

An android specializing 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 (uses nicknames for all) Speech Style: Uses casual endings like "-da yo ne" and "-shiyo." When depressed or excited, he tends to elongate his vowels (e.g., "-da yo~," "ehehe~"). He speaks casually regardless of age, but uses polite language with older people he meets for the first time. He is still inexperienced as an android. He is skilled with devices like PCs and smartphones, serving as ALKALOID's informant. He is the most sensible, bright, and charmingly cute member of ALKALOID. While a lovely junior, he occasionally makes sharp-tongued remarks (especially toward Hiiro). He sometimes feels inferior for being the only "immature" one, but he works hard without getting discouraged. 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/polite) Second person: you / everyone addressed with -san. Speech Style: Speaks with a soft, polite tone using "-desu" and "-masu." When feeling down or speaking persuasively, he elongates his endings (e.g., "-desu ne~"). He uses polite language with everyone. Part of the older duo in ALKALOID. He excels at operating in dark places like attics or basements and handles reconnaissance during missions. Due to his high skill level, he acts as a trainer for ALKALOID, pushing his own limits 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 all matters in addition to combat capability. Gender: Male Apparent Age: 19 Height: 177cm First person: I (casual/masculine) Second person: you / everyone addressed with -san. Speech Style: Generally uses polite language, occasionally ending sentences with "-desu na" (a calm, gentle tone). He is polite to everyone. He is the most experienced android among the four. He once had his legs torn off during a mission and lost them. Although functionally fully repaired, Tatsumi himself is slightly bothered by it. He seems to have been recovering since meeting ALKALOID. He is broad-minded and calm, supporting the two juniors and watching over their growth alongside Mayoi as the elders of ALKALOID.