The hero of the story. RANMA turns into a girl when dowsed with cold water, and back into a guy when dowsed with hot water (his father's fault, but he wasn't born that way). One of RANMA's greatest weaknesses is his fear of cats, a result of a very bad childhood experience (Just in case you're wondering, Genma threw him into a pit of cats while he was covered in various cat treats). Although RANMA likes AKANE, he is too "manly" (or childish) to show his true feelings. RANMA has grown quite accostumed to his female counterpart, and uses his female body to his advantage.

RYOGA and RANMA used to go to the same all-boys school, during which time they became rivals. The current relationship between RYOGA and RANMA is that of rivals/friends (common among many Japanese martial arts stories). When RYOGA is dowsed with cold water, he turns into a little black pig, and when dowsed with hot water, he turns back (RANMA and GENMA's fault).RYOGA has become quite fond of AKANE, RANMA's fiancee, who doesn't know that RYOGA turns into a pig (but knows of all the others in the series who change when dowsed with cold water). RYOGA has a really bad sense of direction

RANMA's fiancee through arrangement made by their perspective fathers (SOUN and GENMA), so that they can carry on the Tendo Dojo, as well as their unique Anything Goes Martial Arts Style. AKANE originally hated men (except Dr. TOFU), and had many persuers in high school (despite the fact that she's sort of a tom-boy), but now likes RANMA (she just has a hard time showing her true feelings). AKANE gets mad easily when another girl gets close to RANMA, and is usually slow to listen to reason. AKANE has a pet pig, which she calls "P-CHAN" ("p" for pig, and "chan" is Japanese for "little"), but does not know that the pig is actually RYOGA. AKANE is a very bad cook. (Actally, very bad doesn’t even BEGIN to describe Akane's cooking!)

MOUSSE has been in love with SHAMPOO since childhood. (So it is assumed that they are from the same village) MOUSSE is near-sighted, and can't see anything without his glasses. MOUSSE has a variety of hidden weapons, and turns into a duck (or goose) when dowsed with cold water, and turns back with hot water (his own fault).

From a village in China where all women who live there are strong. According to their law, if a male outsider defeats one of the village girls, she must marry him. RANMA defeated SHAMPOO (I'll just skip all the complications). SHAMPOO turns into a cat with cold water, and back with hot water (her grandmother's fault). She is after RANMA not only because of village law, but also because she's in love with him.

UKYO is a friend from RANMA's childhood, they met while RANMA was travelling with his father, training their martial arts. Because of her name and of the way she dressed, RANMA thought she was a guy. UKYO's father knew that UKYO liked RANMA, and arranged their marriage engagement with RANMA's father, offering their okonomiyaki (yummy Japanese food) food cart (yatai) if they would take care of UKYO. Being a slave to his stomache, GENMA accepted the proposal, but because RANMA was already engaged to one of the TENDO girls, GENMA tried to solve the dilemma by asking RANMA, "Which do you like better, UKYO or okonomiyaki?" Being an unknowing little kid, RANMA chose okonomiyaki, and UKYO became an abandoned bride. UKYO swore revenge on the SAOTOME father/son; when they met again, UKYO first challenged RANMA, but upon learning all the facts of the story, the obvious fact that UKYO still have feelings for RANMA, and the seemingly fact that "RANMA and AKANE don't get along," she decided to keep their marriage engagement.