Franklin Clinton: The Good Friend (spoilers*)
Franklin Clinton lived a life of being a hustler and repo-man before he met the two people that would change his life forever, Michael De Santa and Trevor Philips. Franklin's best friend, Lamar Davis, has been a troublesome friend for Franklin because he always needs help getting out of jams. However, Lamar does his best to help out as the best as he can do, but somehow it fails.
Things got more interesting when Franklin met Michael for the first time when he tried to repo Jimmy's car back to the dealership he was working for. This wasn't your average greetings where some guy with a gun appears from the back seat pointing a gun to your head. After the events at the dealership, Franklin decided to go back to Michael's house to apology what he had done. This was the time for Michael to help out Franklin when and for Franklin to help out Michael.
Franklin was introduced to Trevor when all three of them met up together for their very first mission together. After the interaction between Michael and Franklin, Trevor steps in to give Franklin some advice.
GTA V - Franklin meets Trevor
During the game, Franklin and Lamar do missions together and have a good time talking to each other after each mission they do. However, later on in the game, Franklin has no choice to help out Lamar once again after a he was setup again during a drug dealing. Franklin didn't want to help him out again because he was sick and tired of saving Lamar from the stuff he gets himself caught in.
For the final mission that leads to the end of the game, Franklin had to make an important decision to kill Michael, kill Trevor, or save them both from being killed by a private army hired by Devin Weston. As the good friend Franklin is, he can make the choice to save Michael and Trevor. However, the choice is up to the player making the decision of killing either of them.
GTA V - The Final Decision
A friend is a person who will be there for you no matter what happens, even if it means risking their life to save them, (cough) Lamar. Franklin Clinton has Lamar Davis, Michael De Santa, and Trevor Philips at his side to call them as friends. They've been together through rough times together and were able to tolerate each other's problems, especially Franklin.
GTA V - Franklin Trailer