The group reach upon a room with several doors to choose from. Kurama tells them that only one door will lead them to their path and the others are gateways to hell. Kuwabara, having the highest "luck factor" of the four, decides to choose the door they will venture, since he senses a strong spiritual energy inside. He opens the door expecting a strong demon to encounter because of the strong energy he sensed, but finds a tiny rat that crawls around.. Gosh.

They continue towards the path Kuwabara insisted, and they find themselves in some kind of room with weird dragon carvings around. As they enter they come upon another sacred demon - Seiruu. He is an ice demon, and he has enormous strength worth not underestimating. Suddenly Seiruu greets another guest, and the four are surprised that someone was following their tracks - Its Byako! He's still alive after burning down the sea of lava and comes to Seiruu begging for help. But instead Seiruu uses his ice attack and freezes the heck out of Byako, then pulverizes him, and Byako finally dies.

Kuwabara gets enraged about Seiruu's lack of respect and confronts him. Just then Hiei steps in his way, and decides he will avenge Byako's untimely death and takes off his cape and brings it down the head of the dead Byako. Hiei draws his sword - and the battle begins. Seiruu uses ice attacks but Hiei is too fast and avoids everything Seiruu gives, thus freezing the whole room... now the whole room is wrapped in ice and Hiei has no where to go.. he barely avoids Seiruu's next barrage of ice attacks, but gets his left leg frozen in the process. Now his speed his reduced significantly with a frozen leg. However things are just warming up. Hiei draws his sword and plunges into Seiruu - as Seiruu attacks with ice. Hiei goes down, both feet and one arm frozen, and Seiruu remains standing, unharmed.

Seems like Seiruu has gained the upper hand as Hiei's speed is drastically decreased with his body frozen. Just then Hiei stands up and startles Seiruu as he unleashes his fire spirit and melts the ice in his body - He is back to his normal self. Seiruu decides to attack again with his ice shards but then suddenly blood rushes down from his forehead... and then in a blink of an eye his dead! Kuwabara was surprised by this turn of events and Hiei explains that when he plunged his sword towards Seiruu earlier he nailed him around 16 times in a fraction of a second without Seiruu even knowing he's hit. He also allowed himself to be hit by the ice attacks to deceive Seiruu even more.. Now Hiei has grown drastically powerful but the important thing is.. he has learned to trust his comrades.

Meanwhile in the other world Botan gets trapped by more and more people possesed by the insects, but suddenly a weird melody tunes in and all the people who were possessed by this mind-controlling insects are rapidly heading towards Yusuke's school.. something's up. We then see a brief look at Suzaku, the leader of the demons. With the three other demons gone, he is the only one left and launches his next strategy which is to invade Yusuke's school and capture the one most important to Yusuke... as the four hurries towards the top of the castle to face him, not knowing something horrible is about to happen in the human world...