Techniques: Very good martial artist, one of the best. May have trouble with a new opponent at first, but once he adapts to their style it becomes almost child's play to him. The only two people who could still give him trouble are Happosai and Cologne, but they've been around forever so it's no surprise.
Neko-ken "Cat Fist" - When exposed to cats for a certain amount of time, Ranma's fear makes him start acting like one. Can slice through anything like he has claws. He's nearly invincible in this state!
Kachuu Tenshin Amaguriken "Chestnuts roasting on an open fire" - Learned it by taking a bunch of chestnuts out of a fire without getting burned. Lets him punch (or kick) very rapidly, sort of like a hundred hand slap from Street Fighter 2.
Hiryuu Shouten Ha "Heavenly Dragon Ascension Wave" - Uses his opponent's hot battle aura to create a whirlwind that sucks up his enemies and slams them into the ground.
Moko Takabisha "fierce tiger domineering" - similiar to a move of Ryoga's, uses one's confidence to project a "ki" forced air blast.
Character Breakdown:
Comes across as a jerk that speaks without thinking, inadvertanly insulting people. The way he was raised has a lot to do with this. For ten years of his life, he knew nothing but traveling and fighting. Genma's apparently wasn't reall big about teaching much besides fighting. In a strange way, it was Genma's way of showing affection, and pretty soon, that was how Ranma showed affection for his father in return, as well as affection for anybody else. Hence, how he acts in his relationship with Akane.
Genma didn't really teach him any real social skills, so he does have a hard time adapting to society, but covers it up with arrogance and pride. That's why he tends to say what's on his mind without considering the impact of what he's saying. That's also why he has hard time showing any real affection (as opposed to fake affection, like during the contrary jewel episode).
His behavior does begin to change throughout the series, however, as Akane gets him to open up and teach him to understand people's emotions, and also about his own.
Perhaps his best trait(that he also shares with Akane), is his willingness to help out both friend and foe, turning foe into friend(or at least a friendly rival). He'll help out Ryoga, Mousse, even the Kuno's if they need it. Of course, his mostly hare-brained ideas do tend to get him into trouble, or make a situation worse, but his heart is in the right place most of the time.
If you're interested in learning more about the relationship between Ranma and Akane, click here
Techniques:Pretty good martial artist and sensei, if you can survive his training. Even invented two powerful schools of techniques. Not as good as Ranma, though whenever they spar they appear to be evenly matched. Probably because he knows how his son fights.
Umisenken-techniques of the quiet thief. Abilites including fading from sight and attacking from behind. Sealed by Genma because he believed they were too dangerous.
Yamesenken-techniques of the noisy thief. Lots of powerful moves, more lethal than normal attacks. Sealed by Genma because he believed they were too dangerous.
Moko rakuchi-sei "fierce tiger falling down strength"-Place both hands on solid ground, face your opponent, and fawn saying `gomennasai, gomennasai, gomennasai...' ("I'm sorry, I'm sorry, I'm sorry..."), emulating the posture of a tiger fallen from a cliff.(note: Soun Tendo also uses this move! :)
Maken dokoku-ha "demon dog wailing defeat"- First, back out of 'ki' projection range. Then, when you've put sufficient distance between yourself and the aggressor, yell insults ('ba-ka a-ho ma-nuke!').
Jigoku no yurikago "cradle of hell" - A technique Genma uses to prove his strength to Ranma, grabbing him and cradling him in his arms.
Techniques: None really, though she is shown to be able to handle the katana she carries. Since she is prepared to carry out the seppuku pledge if Ranma is not manly, she would have to know how to hold it and how to swing it just right to cut someone's head off. I think she's actually knows how to use it very well, but that's just me! :)
Additional info:
Many people look down on Genma because he took Ranma away from Nodoka so she wouldn't 'spoil their son'. This may seem harsh, but does have some justification in Japanese society.
You see, it is not uncommon for the mother to have a very strong influence on her son, and for him to be very respectful of her wishes. This can become strong enough that when the son marries, he will listen to his mother more than his wife. If she tells him that his wife is no good and to leave her, he may very well do that.
So Genma did know what he was doing when he took Ranma away. In the end, Ranma became a great martial artist, and his mother's influence over him isn't as great as it could have been.