Ways Which Games Use Characters To Promote Gameplay Or Tell Stories
Characters in video games are used in trailers realize by the company to show to players/costumers/gamers how the game is played and the game mechanics that may or will be in the games.
The company will show off the characters and the designs used to make said character along with there background and personality. The creators of said character may realize videos or art books showing early concepts and thought on the making of characters.
The character that the player controls is most likely the one the story is based on or around. In which a character will be developed further making friends or enamels most likely helps in that aspect. Also as the player plays they are made to be connected with the character and get emotionally attached to the character and can make the player emotional (happy, sad, angry, etc) as the story or game progresses
Current Trends and Issues Found With Game Character
Most games have male main characters that the player plays as. Most companies are trying to combat this issue allowing these games to be realized. Horizon Zero Dawn, Life is Strange and Walking Dead game where they are many strong women protagonist.
Another trend that happens in most companies. Their characters are mostly white but some may try to avoid this issue by making a whole new species of creature or a non-humen world or even make it so the race doesn't matter.