Otowa Hyōko is a master of “Shadow Instruments” (Anki in Japanese: meaning concealed weapons / assassin's weapons) and a villain from Rurouni Kenshin.
Otowa was friends with the ninja, Nakajō, whom he would go on nightly killing sprees with and even gave him a version of his Chusen. However Nakajō was killed by Himura Kenshin and Otowa used this as an excuse to join Yukishiro Enishi’s Jinchu campaign against Kenshin. However Otowa just joined it for the pleasure of fighting.
Beginning JinchuAfter Enishi began gathering his allies for Jinchu, Otowa arrived at the mansion Gein had rented at the same time as Inui Banjin. Enishi introduced the two and after Yatsume Mumyōi made himself known from the room above them, Enishi said they would be called the Six Comrades, Otowa interrupted and asked if he couldn’t think of a better name. Enishi said he didn’t really care about the name and explained to them all that the Battosai currently lived under the name Kenshin and killing him now wouldn’t be revenge. He told them that they had to corner the former Battosai and make him recognize his past crimes, then they could sever their ties to try and deliver the final thrust. Otowa said he had no objections and Enishi said he had a plan, but instead of him dictating it to them all, they would have equal responsibilities. He explained the plan to each of them and Otowa left with Inui and Kujiranami Hyōgo to begin the first phase of the plan. He headed to Tokyo by train with Inui and Inui was rearing to go, but Otowas asked him if he knew where to go. Inui didn’t and Otowa said he had strong arms, but his head needed work, then showed him the places they were supposed to go. They split up to launch a two point strike with Otowa attacking police chief Uramara’s house and easily took down the policeman there. The chief pointed a gun at the Shadow Instrument user, telling him to lay his weapon down or he’d shoot him. However Otowa used his Chusen to apparently make the gun misfire without doing anything and said all would be according to his will. He opened the door to let in the night breeze, then said it was time to finish things up and Uramura asked Otowa who he was. However he proceeded to impale his sword into the chief’s hand and told him not to feel lonely, since he’d be sending his family after him. Otowa told Uramura not to hold a grudge against him, but at that moment, Kenshin arrived and said he would prefer to end being the target of grudges. Otowa said there was no rule against finishing the former Battosai off early and told him to draw and try his Battojutsu against his Baika Chusen. When Kenshin did nothing, Otowa asked him what was the matter and Uramura warned the former Battosai that he’d somehow made his gun misfire without touching it. Kenshin asked Otowa why he sought vengeance and the Shadow Instrument user said it would be pitiful to send him to the next world without him knowing that. Otowa revealed it was because of his best friend and told Kenshin to quit stalling or he’d kill Uramura, his family, and the policeman with his Baika-Chusen. Otowa proceed to use it, but Kenshin revealed the secret behind the technique by catching the arrow the Shadow Instrument user fired. Otowa pulled down his sleeve to reveal the arrow launcher that was his Baika Chusen and explained how it worked. Kenshin noted such an invention had to have required much thought and practice and Otowa said his mastery was not in swordsmanship and martial arts, but with Shadow Instruments. Kenshin said if revenge was Otowa’s motive, he would duel, but he had to stop involving innocent people. The Shadow Instrument user pulled his sword out of Uramura’s hand and asked Kenshin if he thought he was stupid enough to fight someone who could catch an arrow. Otowa explained the great power of a Shadow Instrument was surprise and though they were both assassins, he wasn’t Kenshin’s kind. Otowa threw two cubes into the pool outside the house, releasing a poisonous mist and explained it was Kasui Busuen. He went on to say it wouldn’t kill Kenshin, but would paralyze his limbs in minutes and he’d have enjoyed showing him two or three more of his tricks. But Otowa said it was time for Jinchu and left (since Kujiranami was about to fire on the house with his cannon), saying he hoped for another encounter if that were possible. Otowa returned to the mansion where he and the others were told by Enishi that he’d told Battosai they’d have their battle in ten days. Otowa said he didn’t like the fact Enishi had decided on ten days without consulting his comrades. Enishi explained he’d called in some of his men from Shanghai, which is why he had chosen 10 days and Otowa thought to himself, as did Inui and Kujiranami, that in ten days, Kenshin’s head would be his.
Assault on Kamiya DojoAs the ten days came to an end, Enish presented Otowa and the others with upgraded weapons, before they headed out to attack the Kamiya Dojo. They arrived via hot air balloon and Otowa noted it allowed them to get into their zone without being attacked. After Kujiranami was defeated, Otowa and Inui leapt down to fight and after seeing Kaoru and Yahiko, Otowa noted that it was brave of women and children to stay at the battlefield. Kenshin told him not to mistake his opponent and leapt in front of him and Inui, who went to fight Sanosuke. Otowa asked the former Battosai why he didn’t move and if he was going to watch his friend die. Kenshin replied that helping Sanosuke would open Kaoru, Yahiko, and Megumi to Otowa’s attacks, saying he was that kind of man. The Shadow Instrument user said Kenshin understood well, so he would watch Sanosuke die. The former Battosai replied that if he died here, Sanosuke was only that much of a man and Otowa noted he said some good things and he was happy to hear Kenshin’s true feelings. After Gein mobilized his Iwanbo Savage Mode, Otowa pointed out the former Battosai had to move and readied his Baika-Chusen. When Kenshin still seemed like he would do nothing, Otowa asked what was wrong and if he really had to think about it so carefully. However the former Battosai rushed him, slashing his Baika Chusen and used the momentum to head towards Gein. Otowa complimented him on the tactic then said he’d failed miserably, but Yahiko attacked him. The Shadow Instrument user asked if he thought a mere child had a chance against him and tried to fire his Baika Chusen at him. However Otowa discovered that Kenshin had slashed it in half and Yahiko struck him. The boy asked him if he thought he had a chance against the former Battosai, much to his anger. After Kenshin used his Amakakeru Ryu No Hirameki to take down Gein, Otowa said he was quite deceptive to hold back such a move. Once Inui and Sanosuke had finished their battle inside the dojo, Otowa noted it was quiet and the victor must have been decided. He asked Yahiko if he was worried, but the boy said no, since Sanosuke wuldn’t lose and said it wasn’t important. Otowa told him not to worry and he’d kill Yahiko, so he shouldn’t rush him, he was just thinking of the method to use. The Shadow Instrument user asked the boy if he should pierce him with arrows, burn him with acid, or melt him with poison. Otowa said he could easily do any of those things, but it wouldn’t repay the humiliation of this wound, so he’d use the weapon he’d acquired today. He drew his sword, which he called Bishamon’s Sword, and attacked, with Yahiko noting it was pretty dull and thought to himself Otowa was a novice swordsman. As the boy swung at him, the Shadow Instrument user threw a jar at him full of powder. Otowa said it was neither blinding powder or poison, but rather it was Bishamon’s Powder. He explained that just as the name indicated, the sword and powder were a pair, whose power was seen when they came together. Otowa attacked and Yahiko saw he was faster, before leaping back to avoid his swung, but the Shadow Instrument user said running wouldn’t save him. The swing suddenly changed direction to slice into Yahiko and Otowa said Bishamon’s Sword was enchanted and made any novice swordsman adept. The Shadow Instrument user continued attacking and asked how it felt to be slashed to death by a novice swordsman. However Karou figured out that Bishamon’s Sword was magnetic, due to Otowa putting magnets inside the sheath, and the powder all over Yahiko was iron powder. The Shadow Instrument user said she was quite intelligent to figure that out, but pointed out that one knowing the trick didn’t mean one knew how to deal with it. However Yahiko said that was all he need to know and rushed at Otowa, who noted he was just charging like a bull with the intelligence of one. He attacked as well, slashing Yahiko’s cheek, then prepared to finish him, saying the boy shouldn’t take him lightly. However Yahiko used Otowa’s sheath, which he used his pick pocketing skills to grab, to pull his sword to the side, reasoning the sword would be more attracted to that than the iron powder. Yahiko threw the sheath away, taking the sword with it, apparently leaving Otowa defenseless, but as the boy attacked, the Shadow Instrument user revealed he’d been faking. He used his Rikudoko, impaling Yahiko with the appendage like attachments to his clothing, and reminded him he shouldn’t carelessly attack a Shadow Instrument user. Otowa explained that where a Shadow Instrument was hidden was a huge factor, but a superior user of them knew that “how” was more important than “where”. He went on to say at times calling it enchanted made it mysterious and at times disguising it as an unusual accessory made it gaudy. Otowa said he concealed them within his opponent’s psychology and let Yahiko fall to the ground, declaring it was over. The Shadow User instrument commended him for making him use his last resort and he would never forget his name, then declared he was just kidding. As Kenshin came out, he said he would handle the rest, but Yahiko got up, telling the former Battosai to let him keep fighting. After some words of encouragement from Kenshin, the boy faced Otowa again, who said his entertainment was ruined. The Shadow Instrument user thought to himself it was time to flee, since he wouldn’t be able to beat Kenshin, based on his fight against Gein and it would be a shame to get hurt in a fight he joined to enjoy. Otowa decided it would be best to finish Yahiko then flee and told the boy he’d finish him as he drew his sword again. The Shadow Instrument user said it would be a most disgraceful death, before swinging his sword at Yahiko. However the boy used the blade halting technique to catch Otowa’s sword, then attacked with blade crossing. The Shadow Instrument user tried to get Yahiko with Rikudoko again, but the boy got past him and smashed Otowa in the face with his shinai. As he went down, the Shadow Instrument user was left with a crazed smile on his face, shocked at being defeated by someone less than half his age. Afterwards, Otowa was arrested by the police.
Otowa relies on outwitting his opponents and catch them off guard with his Shadow Instruments, which he conceals on his person. He says that he has thirteen of them and has been seen using five. The first is Baika Chusen, which is a small six-barreled arrow launcher worn on Otowa’s left wrist. To add mystery to this one, he paints a symbol (written in Sanskrit saying 'Ohm') on his left palm, which he holds up to distract the person and pulls the trigger with his right hand. The arrows move so fast that it’s very hard for people to see what Otowa’s really doing, so it almost seems mystical. The second is Kasui Busuen, small cubes that he throws into water, releasing a poisonous mist that paralyzes the limbs of those that breath it in. The third and fourth consist of two items, Bishamon’s Powder, a jar of magnet powder Otowa throws on his opponent, and Bishamon’s Sword, a sword that he makes magnetic by putting magnets in the sheath. Because of this, when he swings his sword at his opponent, the blade is automatically drawn to them due to the powder and calls the sword enchanted to add mystery. The last is Rikudoko, a set of six tentacle-like appendages that Otowa wears like some odd garment, which he can suddenly send out to impale his enemy.
- Some mistakenly believe Otowa’s design model was Kazama Sogetsu from Samurai Spirits, but he was actually an original character concept that Nobuhiro Watsuki rejected early on in the series.
- The 6-pronged accessory that Otowa wears was borrowed from Mr. Sinister from X-Men.