Ethan
Ethan is the main character in Pokémon Gold/Silver/Crystal. He is the boy character that you can choose during Elm’s long speech.
Kris
For the first time in a Pokémon Game, in Pokémon Crystal, you have the ability to choose between a girl or a boy (Kris or Ethan). Whomever you choose, the opposite gender character will be one of your friends.
Silver
You meet Silver in New Bark Town. You first see him staring into the professor’s lab at the starter Pokémon. Once you’ve left town, he makes his move and steals one of the starter Pokémon and has you battle him. At first, his name appears as ??? as you don’t know who he is. Silver is found out to be Giovanni’s son, a part of Team Rocket.
Mom
Mom in these games makes a small role. She will offer to save some of your money that you win each battle. You can speak to her to withdraw the money from her.
Team Rocket
Team Rocket is back! After Giovanni decided to disband this evil team, some of the members decided to continue this team. You’ll encounter these villains in the Goldenrod take over and other events.
Professor Oak
He’s back! You meet Professor Oak in Pallet Town to have him evaluate your Pokedex. He doesn’t do much in these games like in the previous game.