He gets his super human powers from the chemical called "Big X", which gives him the ability that makes him grow and expand without limits.
He is shown in the famous manga and assorted versions of the anime as a child robot, usually wearing shorts (which are actually part of his body), identified by his trademark, two pointy "cowlicks" on the front and back of his head.
In the manga, his good nature and incorruptible heart, combined with an array of powers, put him on a quest to protect robots and humans from villainous conquerors and alien invaders.
Black Jack (ブラック・ジャック, Burakku Jakku) is a cold-natured, eerie, yet kindhearted and ingenious surgeon is one of Tezuka's dearest creations, despite the fact that in the present day he receives little credit compared to his rival Astro Boy.
Despite his outlaw status, he is considered a miracle worker with his incomparable surgical technique and power of diagnostic analysis.
His operations are generally over 10 million yen, but he more frequently helps the unfortunate for free or a token payment.
He is sometimes accompanied by his short-tempered adopted daughter/assistant, Pinoko and can be recognized by a large cape, loose trench coat, and blue, black or red string tie (depending on the media) with black and white hair, dark eyes, and a graft of dark skin across the upper left of his face.
In the animated film Marine Express and the video game Astro Boy: Omega Factor, Don Dracula is a villain who works for Sharaku.
His typical role is that of a detective in other Tezuka materials, with sometimes a nephew/assistant named Ken'ichi ("Ken" or "Kennedy" in English versions of the Astro Boy TV series).
In the 2003 Astro Boy series, he is called Wally Kisaragi, and in the English-language manga, his "Higeoyaji" nickname is translated as "Mustachio".
His trademark characteristic is to confront danger with a comical wild-eyed panic, then after a moment recapture his composure and vigorously attack the threat.
The manga world was becoming more focused on more complex characters, and Kenichi embodied the one-dimensional, wholesome, "good boy" status of early childhood, but not much else.
After he was retired as a main protagonist, he would usually take a supporting role in other stories, such as Astro Boy's classmate and Leo's friend in Jungle Emperor.
In the Astro Boy: Omega Factor video game he is initially the real identity of the villain, Deadcross, but falls in love with - and is reformed by - Princess Sapphire, and remains with her in the distant past to help her try to avert the demise of the continent of Mu, similar to what happened in the Marine Express film.
The Phoenix (火の鳥, Hi no Tori) is an immortal alien entity that takes the physical form of a legendary magical mythological bird.
She originally appeared as a black-clad warrior in Prime Rose, a comic series in Weekly Shōnen Champion, which was made into an animated movie in 1983.
Sapphire (サファイア, Safaia) is a young woman with slightly curly dark hair, who first starred in Princess Knight.
She is the queen of the Mu civilization in the animated film Marine Express and in the Astro Boy: Omega Factor game.
A running gag throughout Tezuka's work show that a lit candle will stand upright if placed in the notch.
Duke Red is a tall man with a large, hooked nose and spiky hair on the back of his head.
He also played the title role in Osamu Tezuka's rendition of Cyrano de Bergerac and Prince Siddartha's doctor in Buddha.
He made a few appearances in the Astro Boy manga (such as a mad scientist or a murdered priest) and other Tezuka productions, sometimes under the name Akai ("Red" in Japanese).
Hyoutan-tsugi, also known as Gourdski, is a gag character, a small pig-faced patchworked gourd creature that puffs out smoke.
Mitchy, also known as Michi, is a young girl character whose most relevant role is as herself in Metropolis where she is an android who changes from male to female as a method of disguise, similar to Princess Sapphire.
In the anime adaptation, she is replaced by Tima, an original character that is explicitly stated to be a gynoid, unlike Mitchy who changes gender.
He appears as the Superintendent of Police in Osamu Tezuka's Metropolis, also as the Atomic Energy Chairman in the manga version of Nextworld.
Professor Ochanomizu is a mentor of Astro Boy; often seen in Black Jack in positions of authority (councilman, company president, etcetera).
Inspector Tawashi is a police detective with a distrust of robots and therefore has a feud with both Professor Ochanomizu and Shunsuke Ban.
Rainbow Parakeet is a tall young man with bobbed blue hair, red-tinted sunglasses, a white coat and ascot, and dark pants and gloves.
Spider is a gag character, a cartoonish and short man in a black robe, long nose, one hair, stretching an arm and often bouncing.