When Ryoga believed the breaking point could kill people, he used it freely against Ranma.
Yes, it's true that at first he wanted to kill Ranma. It's also quite obvious that he changes that stance over the course of the manga--as evidenced by all the times he doesn't kill Ranma given perfect opportunities to (after he beats Ranma in the Mark of the Battling God arc, after he beats Ranma in the Shi Shi Hokodan arc, etc.) and all the times he saves Ranma's life. (first Taro arc, Phoenix Mountain arc, etc.)
The only reason Ryoga wanted to be rid of the mark of the gods was because of how embarrassing it looked, otherwise he had no problems beating up, even perhaps killing Ranma with it.
Sure. Which is why he went ahead and killed Ranma with it when he thought that Ranma wasn't going to be able to beat him.
Except that he, y'know, didn't.
That arc is very strong evidence. Unfortunately, it's evidence exactly against the point you're trying to make with it.
Even when Ranma was weakened by the ultimate-strength moxibition, the most likely reasons he didn't want to kill Ranma that way was because it wouldn't prove he was better than Ranma, and it would probably make Akane dislike him if/when she found out, and he still wasn't opposed to beating Ranma up a bit in his weakened state.
On the basis of what evidence are you pulling these "most likely"s out of wherever? Even with the blessing of everyone around--including Ranma--to try and kill him in his weakened state, he quite simply can't do it, despite his best efforts--not until Ranma convinces him that he's raped Akane.
If you want to claim that everything that's said about Ryouga's motives in that whole arc is all one big deception, I suggest you supply some evidence for that speculation.
...and there is something in it for him in most cases.
Oh, please. He's willing to feed someone who had just tried to rob him, and then started to walk away without any repayment at all. He's willing to actively defend his arch-rival out of a dislike for seeing the weak get picked on.
Having him protect threatened innocents is entirely in character for him.
When Ranma pretended to be Ryoga's long-lost fiancee around the time of Ukyo's into, Ryoga tried to rape her as soon as they were out of sight, despite her protests and resistance once he started grabbing at her clothes and pushing her down.
Rape? All we see is him glomping a girl who was not only hitting on him, but who had just glomped him just a little bit ago.
Compare:
http://ranmahentai.ranma.ws/RanmaManga/Book12/RM12-157.jpg
As you can see, the circumstances are almost exactly identical--except that this time the camera follows him. Crying "rape" is not merely going beyond the evidence, but is also, in fact spectacularly OOC from his established behaviour in similar situations.
While Kasumi, a character who is usually completely uncaring about the feelings of others and oblivious in social situations played cruel pranks while possessed by the oni, Ryoga went about trying to rape Akane.
...um, what?
http://ranmahentai.ranma.ws/RanmaManga/Book29/RM29-126.gif
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No, Ryouga isn't perfect. Yes (like virtually all of the other characters in the series) he can be a bastard from time to time. But he also shows a definite capacity for remorse, and to learn from his mistakes.
The story of his growing friendship with Ranma is, in many ways, my favorite part of the whole manga. Compare the first volume of the manga with the last one--Ryogua going from being out for Ranma's blood, to the scene in Jusendo where, Akane believed dead and Ryouga himself grief-stricken, he still manages to hold himself together long enough to try and comfort Ranma.
There are many others (another favorite being the image of little P-chan somehow managing to drag Ranma to safety after he goes off the waterfall fighting Taro) but those two bookend the series quite nicely.




