Mysterious Yondaime

Minato Namikaze is the name of the 4th Hokage (Yondaime = The fourth...something like that) Yes, he did die the night Naruto was born using a similar (or the same) technique as the 3rd did when sealing orichomaru's hands. By using that, the user forfeits his own life. No matter the rumors you hear about him being the leader of Akatsuki, he's not alive.