Yakushiji Tenzen (japanese: 薬師寺 天膳, hiragana: やくしじ てんぜん, rōmaji: Yakushiji Tenzen) a major character featured in the Japanese anime Basilisk: The Kouga Ninja Scrolls and the series' primary villain.

As the second in command to Ogen, Tenzen was chosen to be one of ten fighters to represent his clan of Iga Tsubagakure against the chosen ten of the rival Koga Manjidani clan. Due to Princess Oboro's hesitance to fight, Tenzen is able to completely usurp her authority following Ogen's death to become Iga's de facto leader.

Although his initial impression is of a pragmatic fighter concerned solely for the honor and future of his clan, Tenzen is actually a sadistic and mendacious individual who revels in conflict and bloodshed. He fights with a ruthless tenacity and won't hesitate to involve innocent bystanders to guarantee a victory. He also lusts after Oboro and desires to take her for his wife in order to become the true lord of Tsubagakure. Even if he has to rape her to do it - which he attempts at least twice over the course of the series.

Similar to Himura Genma of Ninja Scroll, Tenzen's power is one of regeneration and immortality. He was born sharing his body with a demonic symbiote that usually conceals itself so that only its closed eyes are visible as a wart/growth on each of Tenzen's ears. The creature seems to awaken whenever Tenzen has been wounded or killed, moving through his body to regenerate Tenzen by 'eating' his wounds and restoring any ravages of time or battle Tenzen may experience. Thanks to his powers, Tenzen was already over 200 years old by the time of Basilisk's beginning though he looks no older than 40; granting him a lifetime of martial and tactical abilities that surpass any of his clansmen. Even when decapitated, Tenzen can still regenerate if his head is placed back onto his body with his twin sealing the cut. Reviving from death however seems to be even more painful for Tenzen than dying itself and has greatly contributed to the deterioration of his sanity.

In the Japanese original anime, Tenzen is voiced by Sho Hayami and in the Funimation English dub by Mark Stoddard.

 

Tenzen VS Jubei (episode 3): After encountering Jimushi Jubei on the road to Sunpu; Tenzen sends Koshirou, Hotarubi, Nenki, and Rousai to seek out Kazamachi Shogen and take the Koga's battle scroll while he stays behind to interrogate Jubei. When he demands Jubei reveal the secrets of the Koga's techniques, Tenzen winds up getting stabbed through the heart by Jubei's sword who then leaves to follow Tenzen's subordinates. Tenzen quickly recovers though and reappears before Jubei, cutting him in half lengthwise before the quadraplegic ninja could kill him a second time. With his slain enemy's own blood, Tenzen marks off Jubei's name from the Iga scroll and burns the Koga's copy, ensuring a tactical advantage for Tsubagakure.

Tenzen VS Koga Shinobi (episode 5): After destroying the Koga's copy of the battle scroll, Tenzen led four of the remaining Iga ten (Koshirou, Hotarubi, Nenki, and Roussai) in a sneak attack on Manjidani. Infiltrating the village, the five Iga find themselves intercepted by Kasumi Gyoubu and a squad of Koga shinobi. Although Tenzen claimed the Iga came as friends, Gyoubu had overheard their true intentions and ordered the ninja to attack. A brief yet violent battle followed where several of the Koga were killed before Muroga Hyouma appeared and ordered the attack off. Citing that the Koga had attacked first, Tenzen displayed a manjidani shuriken thrown into his sword scabbard as proof (most likely planted there by himself) before escaping with his comrades. With the advantage of surprise gone, Tenzen realized that the Iga's best hope for victory was to kill Gennosuke before his comrades alerted him to the treaty's nullification.

Tenzen VS Gyoubu (episode 15): After Kasumi Gyoubu interrupted Tenzen's attempted rape of Oboro on the boat to Sunpu, Tenzen recovered and challenged him to a duel. Gyoubu merged with the deck and Tenzen, in an attempt to draw him out, intentionally killed one of the sailors; the body falling overboard and almost hitting Akeginu as she tried to climb back onto the ship from when she failed to rescue Amayo Jingoro. As Tenzen accused Gyoubu of being cruel for putting innocent bystanders at risk, Gyoubu retorted that the Iga had no right to call him cruel after they murdered his father. Tenzen ridiculed Gyoubu for seeking revenge over such a trivial thing and successfully enraged Gyoubu into attacking. From his hiding place in the decks, Gyoubu hurled the crates scattered around the ship and succeeded in knocking Tenzen's sword out of his hand. When Gyoubu reappeared, Tenzen dodged his enemy's unarmed strike and maneuvered himself in front of a nearby child as Gyoubu picked up Tenzen's sword to deliver the final blow. At the last second, Tenzen dodged and Gyoubu wound up striking the child's father instead which, as Tenzen guessed, caused Gyoubu to freeze in shock. With Gyoubu distracted, Akeginu sprayed him with her blood mist and successfully marked him when he tried to merge again, allowing Tenzen to thrust his katana into Gyoubu's heart as he transferred onto a nearby wall. With his enemy dead, Tenzen marked off Gyoubu's name from the battle scroll along with Jingoro's and both Mino Nenki and Hotarubi as he hadn't heard back from them yet. Tenzen then announced to the remaining Iga that in the end they would be the only clan left standing, with a glance to Oboro that warned her next time she wouldn't be able to escape him.

Tenzen VS Hyouma (episode 17): Arriving at port shortly before the Koga, Tenzen left Akeginu to watch over Oboro at a nearby inn while he and Koshirou set out to eliminate their enemies. While Koshirou used Ogen's hawk to lead Gennosuke and Kagerou away, Tenzen hid in the tall grass and prepared to strike out at Muroga Hyouma and another hooded man he believed to be Kisaragi Saemon. Admonishing Hotarubi and Mino Nenki for failing to seal the Koga leader's eyes with the Seven Days of Darkness, Tenzen was shocked to hear the hooded man call out to him as he emerged not with Saemon's voice but with that of Gennosuke. Realizing that the Gennosuke chasing after Ogen's hawk was actually Saemon in disguise, Tenzen watched as Gennosuke removed his hood and laughed when he saw that Hotarubi and Nenki had succeeded after all.

As he drew his sword and pointed it at Hyouma, Tenzen announced he had hoped to let Gennosuke live long enough so he could watch Tenzen obliterate the Koga before taking Oboro as his wife but now he was going to kill both of them right here and now. Despite Tenzen's threats, Hyouma said neither he nor Gennosuke wished to fight and instead asked Tenzen to lead the Iga back to Tsubagakure so that Gennosuke might have a chance to plead with Ieyasu to reinstigate the Hattori truce before any more lives were lost. With a mixture of amusement and contempt, Tenzen rebuked their offer of reconciliation as he threw himself against Hyouma and successfully trapped him by stepping on his enemy's foot. As Tenzen pressed his blade against Hyouma's throat, Gennosuke said that he would indeed not see Tenzen and Oboro's wedding because Tenzen was going to die right then and there. Tenzen mocked Gennosuke's threat as madness and looked back to Hyouma just as Hyouma opened his eyes and unleashed his Dojutusu, compelling Tenzen to slit his own throat open instead.

When Kagerou and Saemon returned after losing both the hawk and Koshirou, Saemon stripped Tenzen's body and copied his appearance before leaving him on the bank of a nearby river. When it was certain no witnesses were present, Tenzen's demon awoke and sealed his throat injury before reviving him in a heaving spasm. In the anime, as Tenzen makes his way back to the other Iga, he vows to Ogen that this time everything would end as he had envisioned.

Tenzen VS Saemon (episode 20-21): Tracking Oboro and Akeginu to the inn where Ofuku had them under her protection, Tenzen learned from Ofuku's samurai that he and Akeginu had left only moments earlier. Realizing that Saemon had copied his appearance, Tenzen disguised himself as one of Ofuku's samurai and accompanied a squad of them to the bridge where Akeginu had been taken to fight with Kagerou. Arriving to late to prevent Akeginu's death, Tenzen questioned Saemon and learned that Kagerou would be arriving at the Inn under the pretense of being Tenzen's woman to eliminate Oboro. Maintaining his own facade, Tenzen asked Saemon if it was true that he was an immortal ninja who could survive any injury and successfully distracted Saemon enough for one of the samurai to thrust forward his spear and impale Saemon through the stomach. As he revealed his true indentity, Saemon plunged down the shaft of the spear in a suicide attack but was unable to defend against the other samurai as they skewered him on their spears. As he leaned back dead over the railing of the bridge, Tenzen remarked that Saemon's one mistake was to impersonate him.

Tenzen VS Kagerou (episode 21-22): Continuing on the journey to Sunpu with Oboro and Lady Ofuku, Tenzen waited for Kagerou who finally appeared at the next Inn the party stopped at. With Ofuku's samurai watching from behind a wooden panel, Tenzen (under the pretext of Saemon in disguise) told Kagerou that in order to convince Ofuku that Kagerou really had betrayed the Koga; they were going to have to prove it and promptly began to rape her. Tenzen wasn't aware however that Kagerou's breath became toxic during sexual arousal and was poisoned when she realized his true identity and allowed herself to be taken. With the help of his symbiote, Tenzen later recovered and recaptured Kagerou as she attempted to kill the sleeping Oboro. As he waited for Gennosuke to show himself; Tenzen dragged Kagerou to a nearby temple where he lashed her to a pillar and savagely tortured her by shooting poisoned needles into her stomach to spell out the word Iga. Kagerou would later die from Tenzen's abuse following his fight with Oboro and Gennosuke.

Tenzen VS Gennousuke and Oboro (episode 22-23): The climactic fight of the series. As he continued to cruelly torture Kagerou, Oboro appeared and desperately begged Tenzen to show her mercy. Tenzen mocked Oboro's plea and pointed out that using Kagerou as bait was her idea to begin with before he grabbed ahold of Oboro and through her to the floor of the temple. As Kagerou's poisoned breath was triggered by sexual excitement, Tenzen wanted to see if watching him have sex with Oboro would have the same effect. Then he'd have Oboro use her Mystic Eyes (which would soon come unsealed from the Seven Days of Darkness) to neutralize Kagerou's powers so Tenzen could safely have sex with her as well. Tenzen pinned the struggling Oboro beneath him and had just begun to forcibly remove her kimono when Gennosuke appeared to rescue Kagerou.

Knowing that Gennosuke's eyes were still sealed by the Seven Days of Darkness ointment, Tenzen applauded Oboro's plan to draw Gennosuke out of hiding before throwing himself into battle against the Koga leader. A vicious fight ensured as Tenzen fell further and further into the grip of a bloodlust fueled by over 200 years of suffering the pain of experiencing death and rebirth as his symbiote repaired whatever minor injuries Gennosuke was able to inflict upon him. Confident in his victory, Tenzen arrogantly boasted that he had manipulated both Koga and Iga for centuries into maintaining their hatred for each other and had even been responsible for the Koga attack on Tsubagakure that turned Danjou and Ogen from lovers to enemies.

As he told Gennosuke that if he wanted to blame someone then he should blame Ieyasu for nullifying the truce as well as himself for being born a Koga, Tenzen charged forward and successfully stabbed Gennosuke through the shoulder. Instead of going down however, Gennosuke seized Tenzen's blade with his free hand and held him in place for Gennosuke to behead Tenzen with his own sword.

Moments later, Ofuku and her samurai found Tenzen's remains and placed his head back onto his body. But as the demon began to reattach his head, Oboro (whose eyes had finally come unsealed moments earlier) stared into Tenzen's eyes and began to neutralize his powers. Tenzen struggled against her but was unable to resist the strength of her Mystic Eyes and finally died once and for all as his head fatally hemorrhaged. In the end however, Tenzen had the final laugh as his demon took control of his body and revealed to Ofuku where Oboro had hidden the unconscious Gennosuke before Oboro could expel it from his body; ensuring that the final battle between the remaining chosen ninja would occur.

 

In the anime, his background is different from the manga version. The creature is neither a demon nor his unborn twin brother, but his mother's ghost; an Iga ninja who was killed by her lover (a member of the Kouga ninjas and Tenzen's father). Baby Tenzen was cut from his mother's womb after her death and taken to be raised as a Koga, but her spirit remained in his body and the adult Tenzen would later defect to the Iga in order to seek revenge for his mother's death.

In both versions, it's suggested that Tenzen was partially controlled by the creature inhabiting his body in a way not unlike Spider-man was with the Venom symbiote.

It's also revealed in the manga that Ogen had at first thought to engage Oboro to Tenzen and not to Gennosuke, but ultimately decided against it. In contrast, the anime suggests that he and Ogen had something of an antagonistic relationship with Tenzen frequently attempting to manipulate or usurp her authority; although he was nowhere near as successful with Ogen as he was with Oboro.