Haruto Saionji

An heir to a rich family and Student Council President. He, along with Hiruda, was transported to End Earth before the other main characters. When he first encountered his old friends in End Earth, he was revealed to be an enemy. He became the Emperor of Baelgard, and goes by the name "Traihard."

Like Souma and Kiriya, he is also a Soul Blader, and chooses to draw swords from Baelgard's four guardians, which includes Reia Hiruda. Seeing Soul Bladers as "chosen ones," he offers Kiriya and Souma to join him in his crusade. Saionji plans to conquer all of End Earth, under the pretense that he is actually "saving" it from darkness. His plans, however, were thwarted by Killrain's release of dark energy.

(Source: Wikipedia)