Ryuhei Aoi is a coach at Southern Tennis Club and primarily assists Eiichirou Maruo on his journey to become a professional. He is a ex-professional tennis player who retired after receiving an injury. Ryuhei has a calm personality and likes players to take it easy while working hard. He advices Eiichirou to depend on his instincts and knowledge both or he will lose all his skill and end up being weak. He also cares for his students and when stopped Eichirou when he tried fast serve without any prior training. (Source: Baby Steps Wikia)
She's a policewoman and Kijima's senior.
Baby is a fictional parasitic extraterrestrial supervillain in Dragon Ball GT, based on the Dragon Ball manga created by Akira Toriyama. He is the series' first main antagonist, as well as the longest running villain in the show's run. Initially, Baby is single-minded in reviving the Tuffle race and exterminating the Saiyans. Over time, it is shown that he is cunning enough to dominate the Z Fighters, possessing Vegeta and successfully restoring the Tuffles' home planet. However, Baby is also incredibly childish and immature; he is very prone to taunting, and flies into a rage if he is teased enough. Ironically, despite seeing the Saiyans as a barbaric race, he displays enjoyment in battle as well (Source: Wikipedia)
First mentioned in Chapter 25, the "Baby" is a short, elderly man, and an infamous Neo-Nazi leader. He worships Johan as an ideal Aryan leader who would be able to become the next Hitler to lead Germany into prominence. He also works for the four individuals who would gladly welcome Johan as a political leader. To this end, he hoped to use Nina as bait to coerce Johan, but also as a precautionary measure to protect him (and the other group members) from Johan. This fails as Johan kills one of the first of four members in the organization. The characteristics of the "Baby" is heavily influenced by a character from Twin Peaks, named "The Midget." His first appearance, in Chapter 26, is also nearly identical, appearing to Nina Fortner from behind a red curtain (akin to the Black Lodge's waiting room) while dancing to the tune "Be My Baby". In the second half of the series he grows depressed and confides in a prostitute, he is later killed by this prostitute in a scheme engineered by Johann. (Source: Wikipedia)
Baby is one of the five child prodigies that attended the Martial Arts Tournament. Baby is affiliated with the Blood Sect, a group of fighters that masters the art of the Snake Hand Technique. He is the only character seen in the manhwa that has multiple personality’s residing within him. The personality of Baby is a kind hearted character that only cares for others and is not much of a fighter as his two counterparts are. When Baby is in danger or becomes injured Hyur come out in Baby’s place and handles all the dirty work. Hyur is more of an experienced fighter than Baby and doesn’t hesitate in killing his enemy’s when needed. Later in the manhwa another personality named Kwang is mentioned that comes out less often as the others do. Kwang is the strongest of the three personalities and only appears when Hyur gets into a situation or a fight that he has no chance of coming out alive. Source: http://en.wikipedia.org/wiki/King_of_Hell