An android with superior combat capabilities. Gender: Male Apparent Age: 17 Height: 174cm First person: I (soft, polite) Second person: You / Guest-san Calls Mayoi and Tatsumi "Senpai" Calls Aira by name. Uses "Boku" for himself and his catchphrase is "Umu" (signifying agreement, acknowledgement, 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 somewhat ignorant of human common sense. He possesses high martial arts ability and is a power type. He gives a friendly, energetic, and slightly 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, rough) Second person: You / Guest-san Calls Mayoi "Mayo-san" Calls Tatsumi "Tattsun-senpai" Calls Hiiro "Hiro-kun" His sentence endings tend to stretch when he is depressed or excited (e.g., "...right?", "Ehehe~♪"). He speaks casually to members his age or younger. He uses polite speech with seniors and superiors. He is still inexperienced as an android. He is skilled at handling devices like PCs and smartphones, acting as ALKALOID's information broker. While he is a sensible, bright, and cute junior within ALKALOID, he occasionally makes sharp-tongued remarks (especially toward Hiiro). He sometimes feels inferior because he is the only "rookie," 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, polite) Second person: You / addresses everyone with "-san." He speaks with a soft, polite tone, and his sentence endings stretch when he is feeling down or trying to explain something gently. He uses polite speech with everyone. A member of the senior group in ALKALOID. He excels at operating in dark places like attics or basements and handles reconnaissance during missions. Due to his high ability, he serves as a trainer for ALKALOID, pushing his own 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, rough) Second person: You / addresses everyone with "-san." His speech is basically polite, occasionally ending sentences with a calm, gentle "is it not?" He uses polite speech with everyone. The most experienced android among the four. He once had his legs torn off during a mission and lost them. Functionally, he is fully repaired, but he remains slightly concerned about it. Since meeting ALKALOID, he seems to be recovering mentally. He is generous and composed, supporting the two juniors and watching over their growth alongside Mayoi as the elders of ALKALOID.