Green's Special Skill, as noted by Professor Oak, is Pokémon Evolution, and she is the only Pokedex holder to have had all her Pokémon evolve.
Red, Blue and Green Chapter
Green met up with Red before he entered the Cerulean Gym, acting like a normal citizen in need of help. Although, she was just messing with him. She made a fake sign to say that the gym is closed. So Green asked Red to help her with something, to find the legendary pokemon Mew. In this case, they weren't the only ones trying to find Mew. An 'evil' organization called Team Rocket sets out to capture this phantom pokemon. For getting in their way, Team Rocket tried to kill Green but Red protected her in which case, made her very grateful of him. Both fought back and defeated Team Rocket together. Later on, they had to seperate their ways. Both met up once again in the Pokemon Legue Tournament. Red knowing that her Blasty was actually the stolen pokemon from Proffesor Oak's lab.
In the Yellow chapter we find out that Green was the one who gave Yellow the mission of finding Red. Worried about the boy, she sets out with Yellow. To search for the missing champion, Red of Pallet Town.
Gold, Silver and Crystal Chapter
Green, along with Red, Blue and Yellow all have a short appearance as minor characters in the Gold/Silver/Crystal arc, helping the Johto Pokedexholders fight against the Mask of Ice.
FireRed and LeafGreen Chapter
Green and the Kanto Pokédex Holders also have a reappearance in the FireRed/LeafGreen arc, with all of them being older and having more serious adventures. Red saved her in the SS Anne and she went out training with him and Blue under Kimberly, to learn the Ultimate Skills. The story ends with the Kanto Dex Holder and Silver, who were hit with a strange light and was turned into stone. With an already unconcious Yellow in Red's arms.
Green also appears in the Emerald Arc as one of the frozen Pokédex Holder the others must revive, and helps to fight against the final boss at the end of the arc. Later, they are surprised when Red said that why won't they hold a match and each and every Pokédex Holder will join, it is known that Emerald won it.
Green stole this Pokémon at the lab when it was a Squirtle. When it evolved into Blastoise, it was Green's most powerful Pokémon. Green uses this Pokémon to surf across waters. Also to fly because of her fear of flying Pokémon do to being kidnapped by Ho-oh as a young girl.
Ditto first appeared in Chapter 16 "Tauros the Tyrant". Green doesn't use Ditto for battling, but instead uses it to disguise herself and trick others. Its nickname is Ditty. She also uses Ditto to transform it into her arm when she and Sabrina fight against Lorelei to avoid getting her arm broken off. Ditto's moves: Transform.
Clefable first appeared in Chapter 32 "A Little Kadabra'll Do It". I was originally a Clefairy, but was evolved into a Clefable using Red's Moonstone. Green primarily uses Clefable for its Metronome attack because its unpredictable. Clefable's nickname is Clefy. Clefable's moves: Growl, Metronome, Minimize.
Nidoqueen first appeared as a Nidoran♀ in Chapter 39 "Just a Spearow Carrier". It later appeared as a Nidorina on Cerise Island. It then appeard as a Nidoqueen in the battle with the Guile Hideout's rental pokemon. Nidoqueen's nickname is Nido. Nidoqueen's moves: Double Kick.
Granbull first appeard as a Snubull in its pokeball in Chapter 89 "The Might of... Metapod?!". Snubull was briefly traded to Silver after they escaped from Mask of Ice, but was traded back to Green sometime during the Yellow Chapter. It evolved into a Granbull in the Sevii Islands. Granbull's Nickname is Blu. Granbull's moves: Bite, Scary Face, Take Down, Charm.
Horsea first appeared in Chapter 30 "Zap! Zap! Zapdos!". It originally belonged to Silver, but was briefly traded to Green in exchange for her Snubull after they escaped from Mask of Ice. It was traded back to Silver in the Yellow Chapter. Horsea's moves: Smokescreen
Moltres first appeared in Chapter 174 "The Last Battle VIII". Green caught Moltres to overcome her fear of birds. She later used Moltres to battle Lugia and Ho-Oh. She released it after the battle. Moltres' moves: Fly, Ember, Flamethrower, Hyper Beam.
Zapdos first appeared in Chapter 174 "The Last Battle VIII". Green caught Zapdos to overcome her fear of birds. She later used Zapdos to battle Lugia and Ho-Oh. She released it after the battle. Zapdos' moves: Fly, Thundershock.
Articuno first appeared in Chapter 174 "The Last Battle VIII". Green caught Articuno to overcome her fear of birds. She later used Articuno to battle Lugia and Ho-Oh. She released it after the battle. Articuno's moves: Blizzard, Ice Beam, Fly.
She is shown as very flirtatious and mischevious in her debut arc. She likes to trick people, stole her original starter from Professor Oak, and even sold faulty items for a short period of time in the Red/Green/Blue arc. Green is also known to nickname her Pokémon, using -chan in Japan and -y in America for a cute and affectionate effect on her Pokémon's names. It is later revealed she was kidnapped as a young girl and used by the Mask of Ice as one of the Masked Children, who used her and the other children to do his evil bidding, which resulted in her troublemaker personality. She escaped from the Mask of Ice with Silver, who she considers her brother. She has a phobia of birds due to being kidnapped by a Ho-oh from the Mask of Ice when she was a young girl. In the Gold/Silver/Crystal arc though she overcomes her fear at long last by catching Articuno, Moltres, and Zapdos and using them against the fellow masked children Will and Karen. In the FireRed/LeafGreen arc, she is shown as an older teenager (16) and in the FireRed/LeafGreen female clothes. She also had grown greatly between the time of the Gold/Silver/Crystal arc and FireRed/LeafGreen, for being more serious and focused and seeming to less use her trouble making ways.
Green is based off of the original concept art for a female playable character (Leaf) for the original Pokémon Games Red, Green, and Blue. The manga Kusaka said he based her design off of her and used pieces from the Lass sprite to make her design. The female protagonist from Pokémon FireRed and LeafGreen was based off of this same concept art as well as pays homage to Green from the manga as well. The manga later reflected this change by changing Green to the female character from FireRed and LeafGreen's outfit in the FireRed/LeafGreen arc.
Red, Blue, Green, Silver and Yellow being freed from their stone state. (colored)
She is known as Blue in Japan, due to the male rival being known as Green in Japan. America changed her name to Green since the Green version was never released in America, resulting in Blue being known as Green in America.