Is Yasha coming back?

The story is about a set of twin baby boys who were created/cloned in the laboratory as a part of gene altering/gene therapy experiment. Because of the nature of the project, the twins were born with superior physical strength, supernatural powers and extremely high IQ. Unfortunately, the twins were separated at birth. One of the brothers, Sei, grew up to be an elite bio-chemistry scientist in America. He was assigned to a project where he has to travel to a small island in Japan to investigate an unidentified virus that is spreading on the island. By a freak of nature, he found out that he has a twin brother, Rin, whose evil, dark personality is entirely opposite of him.

What is going to happen when they finally meet face to face? What are their true identities? Why were they separated at birth, what other secrets are hidden from them? Does the fast spreading virus has anything to do with the twins? Who created them? And why?