These are just brief desciptions of the charcters in Ranma. I will try to refrain from giving too much away for those people who haven't seen many Ranma episodes.
Ranma Saotome is the main character of the story. Ranma is a very strong minded, skilled in martial arts, persistant, and compassionate (sometimes). Ranma's objective is to rid himself of the curse that turns him into a girl. Besides the curse, Ranma has many conflicts with the other charactes in the story. Some characters want to fight him or love him depending on if he's a girl or a guy.
Genma Saotome is the father of Ranma. His highest priority is to get Ranma and Akane to marry so they can continue the Any Thing Goes Martial Arts dojo. Genma has only the best of intensions for his son. The only thing about Genma is that he wouldn't be called father of the year by Ranma but he does provide alot of comic relief. Genma gets his son into most of the troubles he experiences in the story. Genma is also cursed with a transformation when splashed with cold water.
Akane Tendo's personality can be easily described as being a tomboy. She is skilled at martial arts as well but not as good as Ranma. She is the Ranma's fiancee but will never admit to it. Akane is also has conflicts with many of the characters because of her relationship with Ranma. Whether or not Akane loves Ranma is the big question in the series.
Nabiki Tendo is the 2nd oldest of her sisters. She is very business like in her manner. Nabiki always tries to figure out how to make money in almost any situation.
Kasumi Tendo is the eldest sister in the family. Kasumi is a kind hearted homemaker. She takes care of the Tendo family with loving care.
Soun Tendo is the father of the Tendo sisters. He has the same goal as Genma, that is to have Akane wed Ranma to continue the Any Thing Goes Martial Arts dojo. Soun is a very emotion man.
Shampoo, besides having a funny name, she is a strong minded chinese amazon warrior. She is persistent in trying to get what she wants no matter what the obstacle. She really wants someone who lives with the Tendo family. Shampoo is also skilled in her amazon martial arts. For some reason, she wants to kill Ranma's girl side...^_- Shampoo also has some kind of transformation with cold water.
Tatewaki Kuno is the captain of Furikan High School Fencing club. Kuno is very artistic in the way he speaks. Kuno talks in much the same way Shakespearian literature sounds. Kuno has a bit of a crush on two girls in the Tendo's house. I wonder who they are?
Kodachi Kuno is the sister of Tatewaki. Kodachi also has a way with words. She is the captain of her gymnastics club but not the type of gymnastics you may think. She has a crush on someone in the Tendo house as well.
Ryouga Hibiki is an extremely strong individual with good martial arts skill. He has this one draw back by having the worst sense of direction. He is in love with one of the girls in the Tendo family. Ryouga also transforms into something when he is splashed with water. The girls find his transformed state kind of cute.
Mousse is a skilled martial artist with various hidden weapons in his sleeves. Mousse also has a draw back as not having the best eye sight when his glasses are off. Mousse is kind of in love a particular amazon. Mousse also has a transformation when splashed with cold water.
Uykou Konji is a skilled cook. She integrates her cooking utensils and ingredients in her martial arts. Uykou is in love with someone who thinks of her as one of the guys.