Resident Evil 4 revisits a few old friends, and also introduces some brand new ones. The characters in Resident Evil 4 are certainly alive with intent and emotion, so getting to know them is of importance. Each character seems to have his/her own story, but more will be revealed as you progress through the game.
Here is some basic information on the major characters featured in this game.
Leon Scott Kennedy
Leon S. Kennedy first appeared in Resident Evil 2 as a rookie cop. Leaving behind the Raccoon City incident, he became a special agent working under special orders from the President of the United States. He is assigned as the bodyguard of the new President of the United States of America's family. But his duties were interrupted when the President's daughter, Ashley Graham, was kidnapped and Leon sets out to rescue her at her last known location: an unknown village where many dangers are waiting.
Ashley Graham
Ashley Graham was kidnapped by an unknown group on her way home from her university. As the President's daughter, she is of obvious importance, and an even greater tool for those who conduct evil. She is also Leon's (and your) objective. She is of utmost importance to be brought back alive and reunited with her father.
Luis Sera
Luis Sera started out working under the bad guys, and was tasked with investigating and experimenting with the Las Plagas (the parasite responsible for all this trouble). He then realizes that he has made a grave mistake in helping the enemy, and starts to help Leon and Ashley through their adventure.
Ingrid Hunnigan
Hunnigan is Leon's link to headquarters. She provides Leon with imporant and information throughout the game.
Ada Wong
Ada Wong, also from Resident Evil 2, is the lady in red that captivated Leon S. Kennedy. Previously believed to have died from serious injury, she re-appears in Resident Evil 4 to aid Leon in his journey. While she does appear to have good intentions, it's obvious that helping Leon is only one piece of her overall agenda.
Bitores Mendez
This tall, scary man happens to be the village's chief. He is mostly responsible for the way that all the human-like enemies act, and is not a person you want to cross. While he appears to carry some importance, you'll soon find out that there are much bigger things to worry about.
Ramon Salazar
Ramon Salazar works directly under Lord Saddler, and resides in a vast and dangerous castle located near the village. While his size is at times laughable, his tactics and attitude toward anything that stands in his way is something to fear.
Jack Krauser
Krauser is an old friend of Leon's, but unfortunately for you, seems to have forgotten that fact for the duration of this game. Jack Krauser is a deadly adversary that shouldn't be taken lightly. He has also had some work done, so it would be wise to steer clear of him.
Lord Osmund Saddler
You'll hear his name spoken throughout the game, but his identity doesn't become clear until late in the game. Who is he, and what does he have to do with Ashley's kidnapping?
The Merchant
A mysterious character who's identity or true intentions are unknown, the Merchant will be encountered frequently throughout the game, in which the player will be able to buy, sell, and upgrade weapons from him. The Merchant can be killed and will not spawn at the location again (but can in future locations); if the Merchant is killed in Professional mode, he will never spawn again in any location.