The stereotypical mad scientist, Dantalion is not liked by most Denizens, even in the Bal Masque, because he would do research on their own people. Among the Trinity, Bel Peol doesn't like him and Sydonay hates him, but somehow Hecate seems close to him, even calling him "ojiisama" and protects him most of the time from getting into trouble with the higher-ups. Often says "-domino" at the end of his sentences.

He had thought his normal days would last forever, until they were ended abruptly by an encounter with a girl with red hair and eyes. He named her Shana. 
Not long after he enters high school, Sakai Yuji&rsquo;s normal days come to an end. He sees something bizarre on his way home: people are frozen in a strange fire, and a monster that looks like a large doll is attacking them. Just when he's about to be killed, a girl in a dark cloak wielding a large sword appears, and slices the monster in half. Although Yuji survives the strange encounter, the girl informs him of a desolate truth: " 'You' don't exist anymore." 
She calls herself a Flame Haze who hunts "Guze no Tomogara"; intruders from another world. She explains to him that he is a "Torch", a substitute of Yuji whose &ldquo;existence&rdquo; has already been devoured. She also told him that he is a special Torch, "Mystes", which contains a precious item in it. When he looks at his chest, he sees within himself a faint flame, just as she said. 
It is in this way that his eternal struggle alongside the girl begins. 
(Source: AnimeNfo)

Continuing from the events of the last series (Shakugan no Shana II), both Shana and Kazumi stand at their respective locations waiting for Yuji to meet with one of them, only to discover that Yuji has disappeared, with not even the slightest evidence of his existence left behind. All is not lost however, as the letters the two of them sent to him still give hope of Yuji's continued existence. As Shana and company search for answers on Yuji's whereabouts, they soon find the truth staring back at them when Yuji reappears in front of them as the leader of Bal Masqu&eacute;. Left with little choice, Shana must now confront her most unlikely adversary on the battlefield in her toughest challenge yet.
 
(Source: Anime News Network)

The heated bond between Shana and Yuji is tested as their paranormal adventures continues. The Flame Haze fends off supernatural foes by night. By day, she contends with a classmate who's also after Yuji's heart. Emotions flare as a suspicious transfer student who resembles a recently defeated Denizen clings to Yuji. His training rises in intensity when they catch wind of a revered warrior in search of her lost lover—who will stop at nothing to extract the power keeping Yuji alive! 
(Source: FUNimation)