Tora

Tora (とら, Tora) is an ancient tiger-like yokai who was released when Ushio pulled off the Beast Spear. Prior to being pin in the basement of Ushio's temple, he was known as Nagatobimaru, famously feared among the yokai community for his sheer strength and powers of lightning. Being trapped in the basement for 500 years, he has great curiosity over modern lifestyle and gadgets. His favorite food is hamburgers, which Mayuko always provides when they meet. He states that he has every intention to eat Ushio and Mayuko, thus will not let them be taken away by other yokai. At the same time, Tora seems to enjoy their company, and he has said that he will not do something as low as attempting to eat Ushio in his sleep, implying he would prefer fair combat. He also explains the reason why he protects Ushio despite saying he'll eat him is that he never feels bored around him. Tora cares deeply about him which he truly tries to deny.

Backstory
During the final battle with Hakumen no Mono, it is revealed Tora was once a human general of Ancient India near 3000 years ago, named Shagaksha. Supposedly born a cursed child, Shagaksha grew up hating everything and everyone around him because of being constantly reminded of the deaths surrounding his birth. He found solace only in fighting in wars and battles, enjoying killing and venting out his hatred. All the while he lived, he was plagued by a constant throbbing pain in his shoulder.

But he found companionship in his attendant, a young boy named Rhama, who idolized his master, and he fell in love with Rhama's older sister. They were the only two people he ever really cared for, and were the only ones to ever make him smile. But then war came again and Shagaksha was called to arms once more. Before heading into battle, he took Rhama's sister in attempts to take her somewhere safe. But as they fled, they unfortunately met an enemy squadron who let loose their arrows on the two. Shagaksha survived but Rhama's sister died. His hatred reached its peak as Shagaksha killed the enemy soldiers and the pain in his shoulder flared greater than ever before when he heard a voice of malevolence inside him. This voice then ripped itself free, revealing itself to be the source of the pain in Shagaksha's shoulder. This voice was Hakumen no Mono.

Hakumen revealed it was once a formless darkness that desired a body. By coincidence it found Shagaksha as an infant and made him its host. Inside Shagaksha, Hakumen fed and gestated on the man's unbridled hatred, which became its flesh and blood. In other words, Shagaksha's hatred gave birth to Hakumen no Mono. The demon fox then revealed as a side-effect of having been inside him, Shagaksha could not die, and destroyed his village to make him even more hateful. Shagaksha ran to his village and found his attendant Rhama on the verge of death. The boy died in his arms and Shagaksha was alone.

As he could not die, he wandered Asia, seeking a way to take his revenge on Hakumen for 400 years. Finally, after hearing about it from a wise man, Shagaksha sought the Beast Spear. When he came to the valley where the holy weapon was sealed, he happened upon a boy he somehow knew was named Kirio. He told him his sad tale and then released the Beast Spear from its seal and became its wielder. Eventually he became a yokai, the first of its kind that came to be known as Azafuse. He forgot his human life and became known as Nagatobimaru. And from there grew cold and started to kill and eat humans, creating a legend for himself.

Later in the series it was revealed that Tora actually remembered his previous memories, when stabbed by the Beast Spear for the first time 500 years ago, however his cold heart refused to acknowledge it and he lied to everyone. The reason for his stabbing is revealed when Tora explained his fated fight with the samurai Beast Spear wielder. The samurai is actually succumbing to Azafuse's transformation but Hakumen no Mono's minions are targeting the Beast Spears aura. As Azafuse is unable to wield the Beast Spear and would forget his human memories, in a last act of desperation the samurai pinned the Beast Spear into Tora's body, which partly Hakumen no Mono's flesh is able to survive the stab and subsequently hides the Beast Spears aura. This also explains why Ushio and Tora continuously encounter more and more of Hakumen no Mono's minions over time as the Beast Spears aura is detected by Hakumen no Mono.

Personality
Tora is many things: He is very arrogant, rude to others, even to his elders, he is very conceited and confident in his abilities and is often fully capable of backing his boastings up with his sheer power. But still, sometimes Tora isn't the brightest, and even acts like an immature child. Upon being freed into the modern world, he is very curious of the technological advancements of Humanity, and has an interest in history (owed to being stuck in a cellar for 500 years), and thanks to Mayuko, he gains a taste for burgers.

Ushio Aotsuki
Tora's bane of existence (and, as much as he denies it, his (likely) best friend) is Ushio Aotsuki, the boy who freed him and wields the Beast Spear. And the human Tora has vowed to haunt until he eats him. Tora never stops reminding Ushio that someday he will eat him, and will often protect Ushio from other Yokai just to make sure they don't eat him before he does, but it is clear that, as much as he denies it, Tora does care about Ushio, as they constantly fight side by side and get into arguments similar to that of brothers in sibling rivalry. But there have been signs that Tora genuinely cares for Ushio, such as when he answered he stays with Ushio because he's never bored around him, and (although he tried to do so once) he never tries to eat Ushio in his sleep, implying he wants a fair fight.

Mayuko Inoue
Tora has vowed to eat Mayuko, although he never threatens her or actually tries to eat her, primarily because he knows if he ate her before eating Ushio, the latter would hunt him down to the ends of the earth. So, for now, he plans to eat Ushio first, before having Mayuko as dessert. He met Mayuko when he helped save her from the Gamin Yokai, mostly because he chose to eat her before they showed up to kill her, and Mayuko has since had a friendship with "Tora-chan", often giving him burgers to eat. Her romantic affection towards him often confuses and embarrasses him, though he reciprocates it in his own gruff manner and becomes quite protective of her, though he frequently tries to deny it with the excuse that he protects her only so no other monster can eat her. And later was revealed how deeply Tora care and fond of Mayuko, since he gets so enraged that the other bakemono captured her just so they can use her to make another beast spear. He's also upset when he heard Mayuko is going to be the next Oyakume, he even promised her that he will kill Hakumen so she doesn't need to be an Oyakume.

Powers and abilities
Tora is a supremely powerful Yokai, armed with several supernatural powers and abilities. Tora is among the most powerful yokai in the series, and as such beholds extremely strong demonic energy (Youki). A clue to his power is seen at the very start of the story: When Ushio opened the cellar in which Tora was imprisonedm it released the collected demonic energy which had built up inside the cellar for 500 years, attracting hundreds, if not thousands, of demonic fish and insects. The first time Ushio met Tora, his energy enabled the boy to be able to see and hear Yokai immediately. Tora's physical power easily exceeds any human's and most Yokai. He once held up a plane and helped it land when its landing gear jammed (albeit being suckered into doing it by Ushio) and came out of it virtually unharmed aside from a few scrapes and bruises. He has shattered huge constructs with his strength alone, and he can carry up to at least three people without being slowed down. Tora can breathe fire and conjure lightning by mere force of will. His lightning seems to generate from his hair but he can focus it through his claws or even summon a colossal storm of lightning from the sky, as he once stated he can make as much as he wants. He can also conjure powerful slicing gales of air, whirlwinds and tornados. Tora can make himself invisible to almost everyone but he can be seen by people who already know of the existence of Yokai, those with spiritual powers, and even an occasional child (but if he is sufficiently weakened he can't maintain his invisibility to other humans). He can easily phase through solid walls like a ghost (although he has shown there are times he can't phase through foreign materials like glass, metal, or concrete, which often led to him comically crashing headfirst into structures he tried to access), and he can both fly and levitate, and is capable of flying at least up to 300 mph. Although he rarely resorts to it, Tora has a certain degree of shapeshifting, as he once took the form of Mayuko and was able to pass himself off as a normal human, but he is not used to the forms he takes other than his original form. He has also disguised himself as ramen in an attempt to eat Ushio, and as a fortune paper telling Ushio he would have terrible luck on New Year (and getting thrown into fire afterwards by a sulking Ushio). Tora can control his long mane of hair to do various tasks, such as simply grabbing, or even making his hair into blades to attack his foes but he doesn't do so much unless he's in tight situations. With his hair, Tora can even catch bullets, and he can even form pieces of his hair into realistic clones of humans, as he did with Asako (however these clones seem to appear near-emotionless and don't speak). There is also some kind of sensory ability in his hair as he can locate someone who has a strand of his hair after they pull the hair, seen when he gave a bit of his hair to Asako so she could locate Ushio and then summon Tora. As he often gets into dangerous battles, Tora will sometimes come out severely injured, as he once got his arm chopped off, but was able to re-attach it, and he even survived getting cut in half down the middle and put himself back together (although he had to keep his two halves tied together for a while or else they would split apart by his losing concentration); Tora even survived getting his head ripped off and was able to re-attach it. And of course, Tora is constantly whacked and bonked on the head by Ushio, almost always leaving him with comical bumps on the head, and in many battles he is gored, stabbed, clawed, etc., but is able to heal quickly given time. Despite being grievously injured from time to time in battle, Tora is able to keep fighting until he wins, proving his endurance and ability to withstand pain is matched only by his will to win.
 * Immense Demonic Power:
 * Supernatural strength:
 * Fire-Breathing/Wind/Lightning Manipulation:
 * Invisibility/Intangibility/Flight:
 * Limited Shapeshifting:
 * Hair-Manipulation:
 * Advanced durability and endurance:

Trivia

 * Though he doesn't seem like it, Tora is almost 3000 years old
 * Tora's name means "tiger" obviously for his tiger-like appearance
 * Tora's prior name, Nagatobimaru, means "far-flyer"