Hazrat Mahdi (pbuh) is the person who enables the Unity of Islam
Excerpt from Mr. Adnan Oktar's Live Interview on A9 TV dated August 14th, 2011
ADNAN OKTAR: Being Hazrat Mahdi (pbuh) is not only by explaining things well. Being Hazrat Mahdi (pbuh) is through success. If a person enables the Unity of Islam, he is the Mahdi (pbuh), do not ever hesitate on that, by the leave of Allah. Other than that, saying that his eyes and eye-brows look like him, his body looks like him [does not count]- they might look alike.. I mean Allah may create that as a marvel. Even the incidents mentioned could look alike.. What is the essential outcome, what is the massed result in the system of the Mahdi? It is the Unity of Islam. Once that is ensured, that is okay. We then ask; "Who had been instrumental in this?" This person had been instrumental; this is the individual. Then Allah knows the truth that individual is him [Hazrat Mahdi (pbuh)].
Once the Christian world becomes Muslim, what would we say? Allah knows the truth this is him, this is the Prophet Jesus Messiah (pbuh). Insha'Allah. For that reason, our brothers should be at ease about this matter. Insha'Allah.