The Deuteragonist of the series known as Kenta Ikegami, Maicching Machiko, is the primary initiator of inappropriate advances toward Miss Machiko. Despite his shamelessness, there may be some underlying kindness within him. He is brilliant yet lazy; if he dedicated half the effort to his schoolwork that he does to devising plans to disrobe Miss Machiko, he would likely score higher than a zero on tests. Machiko herself directly tells him this. He often shouts "Touch!" when he puts his hands on Miss Machiko, though it is not an attack. His catchphrase, "Daiseiko," meaning "great or huge success," is said by him, his friends, and sometimes Machiko when one of his pranks succeeds. When Tenko accuses Kenta of touching her, Kenta confidently states he wouldn't try to hide it if he did, then demonstrates by using Miss Machiko as an example. He is the class clown, constantly causing mischief. Nothing will stop this boy from harassing Miss Machiko; he relentlessly pursues his obsession. All the boys exhibit this behavior, but Kenta stands out as the ringleader, hatching numerous plots to harass or remove Miss Machiko and other female classmates. While his friends have some standards, Kenta's primary goal is to harass every cute female in the show, with Machiko as his main target. He essentially embodies a young Ataru with Goku's voice.

Ichimatsu Matsuno (松野まつの 一いち松まつ Matsuno Ichimatsu) is a character in the series Osomatsu-kun. He is one of the sextuplets. His signature color is purple. His name derives from 市松 (ichimatsu, "checkered"), referring to a check pattern, but with the first kanji replaced with that for "one" reflecting how that kanji is often used in boy names. It is said that he hates his name to be misspelled in the checkered way. Although his place in the order of the sextuplets was ambiguous and not of importance in early media, he is established as the fourth-born son in recent works, most notably the counterpart in the 2015-2018 spinoff Osomatsu-san. Among the sextuplets, Ichimatsu was given the trait of being the "#1 serious" brother by Akatsuka, which has remained consistent to modern descriptions by Fujio Pro. He is usually not name-dropped in outside appearances, or is left to blend in with the rest of his brothers unless there is specific need to identify him. Ichimatsu's appearance differs very little, if at all, from that of his brothers. He wears the same clothing, and his proportions are subject to vary depending on the artist. In the Takeshobo reprints in 1995, he was assigned orange as a color and appeared with his uniform shirt colored that way on a cover (as opposed to the usual blue shirt). Ichimatsu is the most serious and strong-willed of the boys. He is described to be very intelligent, although as he can be as poor as the others at studies and education, it is likely only a marginal amount in comparison. Otherwise, he mostly acts in tandem with the other five. He can act as an older brother-type to younger children and show a kind and caring demeanor [1], but can be just as merciless and violent as his brothers. Because of his practical nature, he tends to have the most money saved up (in one instance 50 yen[2], in another 400 yen[3]).

Nyarome (ニャロメ), created by Fujio Akatsuka, is a prominent character in the later portion of the Extraordinary Ataro manga and part of Akatsuka's Star System. His increasing role in the series lead to a spike in its popularity and the "Nyarome boom", although this would be all too temporary as the series would eventually be ended by order of Akatsuka's editor and Toei in favor of another series (in hopes to emulate the success). The inspiration for Nyarome came from Akatsuka's youth, when he and a friend named Okumura found a stray cat and decided to tie it to a rock, throwing it into a pond. Days later, Akatsuka would see that the cat had seemingly escaped from its likely predicament when he saw it in a field. In thinking back to the animal, Akatsuka recognized it as something that knew no fear and that hadn't given up in its escape, so he and his friends came to view it with respect. This formed the basis for an initial obnoxious cat character, but one that would become synonymous with being a stubborn fighter.

Ataro (ア太郎), created by Fujio Akatsuka, is the protagonist of Extraordinary Ataro as well as a part of Akatsuka's Star System. Ataro is a short young boy with a wide, sloping face and a pointed, jagged impression to his bowl-cut hair. He has small, circular eyes, a pointed nose, and visible freckles. He is often dressed in a long-sleeved shirt and dark pair of pants (often colored blue or green), and wears both a hachimaki and haramaki as well as a pair of sandals. He can also at times be seen to wear his "Yao Batsu" apron around his waist. Ataro has an old-fashioned, Edokko-like temperament that makes him popular with older women in the neighborhood (such as Kumagoro's wife), leading to him being a motivated, polite and friendly young man. However, he can also bear a playful and mischievous side alongside his merchant nature, and is not above teasing the cat Nyarome or even his own friend Dekoppachi. Though he isn't great at school subjects, his math skills when it comes to vegetables and the grocery bill are decent enough.

A hard-headed boy in both a literal and figurative sense, Dekoppachi is Ataro's trusted friend and partner at Yao-Batsu. Though he was not present from the initial stage of the manga, the impact he had as a cast member resulted in him being promoted to an earlier role in both animated adaptations. Dekkopachi was also another case of an Akatsuka character who was granted a name by the readers, with him never having a name stated in-story up until the reader poll and winning vote provided him with one. Dekoppachi is a short young boy, with a particularly large, swollen forehead that results in him having a heavily creased brow. This "stone head" proves to be rather useful in a fight, and is in fact as hard as rock. His eyes are often depicted as simply black dots, and he bears prominent moles on his face as well as a bucktooth. He is often dressed in a single-button shirt and pants, but may wear other clothing as dependent on the setting (particularly in the "Flower of Dekoppachi" spinoff). Dekoppachi is a short-tempered, argumentative but passionate sort of boy who won't give up easily, which can get him into fights but also lead to him to never abandon those in need. He is well-liked by girls, at times being even more popular than Ataro, which can lead to conflict between the two and a positive or negative outcome for the situation.