The facts about this bishounen ninja are obscure, and can only be deduced from what little exposure he has in the anime, and merely reading between the lines in the manga. 

He first appears in volume 4 chapter 7 of the manga (Demon Disappears) and episode 13 of the anime (The Dragon of Fire! The Emergence of The Legendary Flame). On both accounts he spearheads the group that fetches Kurei from the castle, thus interrupting the battle between Recca and Kurei.   

THE URUHA NINJA...  
A long time member of the Uruha Jyusshinshuu, as he can be seen even in the days when Kurei was younger and when Kurenai was in her human form. He is the sole member of the Uruha Izakuchi/Rai subdivision of the jyushinshuu during the UBS. Yup, he works on his lonesome and doesn't need anybody ^_^. He's also noted to be one of the higher ranking officers of the Assassin organization, as when Neon wanted to join the group, she had to ask for his permission first. He's also perpetually seen by Kurei's side, so he seems to be Kurei's right hand man. Kogenai had once described the hierarchy of the Uruha Jysusshinshuu and said that the top men are most powerful. Raiha is one of them. The extent of his powers however, are unknown. Apparenty he has not unleashed all of them.  

He knows many of the Uruha's secrets. He knows members of which not even a long time assassin like Neon knows. The irony of it all is that he knows more the Uruha Jyusshinsuu than they know about him. He knows about each member's profile and powers. An example is this excerpt from Manga vol 10 chapter 5: The Other Semi-Finals II Hiruandon (Day Lamp) 

mikoto : this is not a game, noroi... the opponent this time is that raiha.  
label : jyushinshuu, mikoto.  
mikoto : even though he usually acts goofy, he's truly one of the strongest men in uruha... don't underestimate him...  

kai : was he here just to prove that with his strength, he wouldn't have lost...  
label : jyushinshuu, kai  
kai : or perhaps a demonstration because of his unwillingness to lose...  
mikoto : but the truly frightening fact is his calmness during the battle with noroi. if he really got serious, we would all be in trouble...  

From Volume 20, even Kirin (one of the new Uruha assassins, I think Ura Uruha) who reads minds say that Raiha IS THE STRONGEST MAN IN URUHA JYUSSHINSHUU.  There are two minds in the Uruha that Kirin's mind-reading madougu could not infiltrate. One is Kurei's, the second is Raiha's. This is during the post-Kurei period anyhow. Though how he compares with Rasen (the new guy at the Uruha helm) is *not stated.* 

How powerful is he exactly? Nobody knows, and Anzai Noboyuki *isn't saying* up to volume 24. Though it can be deduced that he is powerful enough to cause anxiety among the members of the Uruha who cam face to face with him in battle (see Mikoto's statements up there). You should see the expression on Soukakousai's face when he first ran into Raiha in volume 20. And especially the way that poor *sob* begged for mercy when Raiha confronted him.  Kirin, who can read even Recca's thoughts, can't penetrate through Raiha's mind. 

THE WARRIOR AND HIS WEAPON... 
Audience : Unbelievable!! It's the first time we see someone who can rival Uruha Kurenai!! That long hair guy is so strong!!0 
As previously stated, Raiha is one powerful warrior. He breezed through the entire Urabutousatsoujin using only his katana (sword) and his shurikens (metal stars). Looking at him, he appears as an ordinary ninja. But he packs in a lot of skill and strength, enough to annhialate everyone in his path. 

 Chapter 4: The Other Semi-Finals I (Stalemate) 
(raiha sama walks in, notice all the girls cheering...) 

girls : ahhhhh-- it's raiha sama!! 
ushino : uruha rai is a one man team composed of only raiha! 
raiha (stuck in the middle of the crowd of girls...) : [uh... can I get through please...] 
ushino : he single handedly dealt 17 defeats and advanced to the semi finals. and now...!! 

Frequently underestimated because of his benign appearance, as he does not possess a lot of impact like, say, Gashakura or Jishou whose mere appearances would make you want to run into the opposite direction ^^;;;. He also appears goofy and clumsy at times. He tripped during the semifinal match as he proceeded to go up the stage. Though this is all a facade. All of the silly things he does are part of his plan. There's a reason for every little funny action he makes. My guess is that he does all this to distract his ooponents so they would let their guard down. After all, he looks relatively harmless. He likens himself to hiruandon, (day lamp). As Kurei would say it (from vol. 9 chap. 3) 

kurei : day lamp... hahah... [are you imitating ooishi kuranosuke? raiha...]  
note : back in edo, he's the leader of the akogishi, and pretended to be a useless person. he was called the hiruandon *day lamp* as his enemies misjudged him, he successfully wiped them out..   

Raiha's battles are often not shown in the manga, heck even in the anime. Other than that brief battle with Noroi where he did a little swordfighting and that battle with Soukakousai in volume 20. He kills the latter with two strokes. One to break through the cauldron (and stabbing the Uruha assassin in the process) and another to chop him into pieces. It appears however, that he is a hitokiri in the tradition of Battousai Himura (*drool drool*). 

He also has an *amazing* ability to appear and disappear in the blink of an eye. Just ask Fuuko *_* who has witnessed this more often than anyone else. He appears out of nowhere and returns there just as easily. He also is quick on his feet. He evaded Domon's punch (Manga vol 9 chap 3 A Quite Peaceful Night), and even manages to put some soda cans on the latter's head ^_^. He does this in a flash. "He moved swiftly and fluently, like a single leaf falling," Fuuko describes.  

Raiha's madougu is the Raijin. And if you know episode 23 or 24 of the anime, you understand that the raijin is the twin madougou of the fuujin. It is one of the high level madougus. Created by Kaima to counterpart the fuujin made by Kokuu. These two madougu makers perpetually compete in making the Hokage weapons. One of the weapons is good, the other one evil. While we all know what the fuujin looks like and what it does. The raijin can be seen in manga volume 17, amongst a bevy of Hokage weapons. According to Kamiya-san, it looks like a large scorpion or an evil-looking version of the fuujin.. 

kurei : I was planning to praise you... but I really can't understand you, raiha. why are you not using raijin? 
(something flashes across the other three jyushinshuu's face.) 
audience : raijin? what's kinda weapon is that? look... those three's expressions really changed. 
raiha (ponder) : hn... can't I not answer that? alright... now is not the time yet--- 

When Recca's teacher (Tatesake Fumio) had that madougu scroll in the first few volumes, and he opened it, it rolled open just enough to cover raijin's design, but showed the words "raijin" on the side...  it obviously has the power of electricity. It posesses a rai crystal and it  also seems to have a spirit like the furry adorable spirits of the fuujin. Not to see the light of day during the Urabutosatsoujin tournament, it was however, used once. In volume 16, Mori Kouran set off the bomb in Tsukino's (Kurei's foster mother and Mori Kouran's wife) body when Kurei lost to Recca in the UBS. Raiha who had left earlier, went to the Moon Palace just in time to save Tsukino from death by diffusing the bomb using the raijin. Kurei often asked why Raiha-kun isn't using raijin, and he would reply that it wasn't time.  

kurei : raiha... you said "now is not the time yet". I don't believe it's because you're scared. then what did you really mean? 
raiha (stand up, perfectly alright) : really, I don't have a reason to fight. (brush off the dust) I'm only here to help kurei-sama advance. (pick up his sword) I am kurei sama's loyal servant... therefore, why do I need raijin now? maybe, when you're in danger one day... then I'll unseal raijin. this is not my battlefield! I'm only a day lamp, and I'll be leaving the field now.
Raiha-kun, by the way, has the main orb of the fuujin. He used it to seal the powers of the raijin. A power, undefined with it's strength that even he, is afraid to unleash it. But he says a great battle would be coming and side by side with Fuuko's fuujin (now with it's central orb) he would fight with his madougu. Now that, is one sight to behold! 

THE PERSON WITHIN... 
Raiha isn't the classic bad guy in the molds of say....Nakago (FY) or Shishio (RK) who are diabolic, scheming, ambitious and all that jazz (Of course Kurei deoesn't quite fit the mold either ^_^). If he wasn't visibly fighting on the other side, he'd easily pass up for Hokage!!! He doesn't look the least bit threatening nor have any signature bad guy stuff (like a laugh or a mannerism or a facial expression). Oh you know what I mean. He doesn't look, sound, dress like a villain. He reminds me a lot of Soujirou Seta and Hitokiri Battousai.  

He doesn't look the part, as he perpetually wears a smile on his face (errr...remind you of anyone ^_^ clue....SS of RK). The only time he does wear a serious look is when he's mad or upset. Usually it happens when people insult Kurei. Otherwise, he's a happy camper. In the manga, you'll often see him sporting an SD face. He also doesn't dress the part, as he often wears a simple ninja outfit in contrast to the cool, heavily-armored, intimidating Joker. He also wields a katana..which doesn't look too scary compared to Jishou's heavy artillery. 

Raiha confesses to having an amiable personality. And he shows it too ^_^. He's polite, addressing people with terms like "sama" as he would Kurei and "san" (Fuuko, no less ^_^). He also says "please" every so often. He's soft-spoken, even if he gets mad (he would warn people about his change of mood). He's an incredibly nice guy ^_~!!! In the UBS, he would often walk over and shake hands with the opponents he had after he defeats them. And there is some sort fo *implication* that he never killed anyone during the matches. He once saved Kaoru from Neon's wrath when the former resigned from the Uruha. And he was nice to Domon even if the latter attempted to hit him. He's also got a sense of humor, laughing at himself when he tripped while climbing the stage. Plus an incredible amount of patience...when it comes to Fuuko that is. He doesn't seem to get peeved easily and is sincerely apologetic. Quiet until otherwise provoked. 

And yet..... 

It was illustrated in manga no. 20 that Raiha has a certain dark side to him. What that is, is yet to be revealed. (So explains why my site is black and white). His personality is sort of like this wanderer I know (Hint...hint...^_^x  "oro"). Kaoru had once said that his mentor is dangerous in a sense. He can...and will kill if it calls for it. Just ask Soukakousai ^^;;; who had a first hand experience in that field.  

Until the time Noboyuki-sensei shows it, we can't really dissect this character. Only *intelligent* analysis will do. For now, we'll have to be content with the little info gathered herein. To see more of this man, click on the navigation bars below.