The Last Warrior who Regressed to the Day of Doom

Have you heard of the Gloria Tower? It is nowhere to be found on Earth, but people know it exists somewhere in this infinite space. The chosen ones must conquer it and reach its last floor in order to receive the [Final Gift]. Some people believe that if you get to the end of it, you will be granted one of your wish, other think you will just be sent back to Earth, while a few ones say you will be sent to a higher realm. In fact, only one person knows what lies at the end of it all. The only survivor of the Day of Doom. The only one who managed to reach the final floor. He was reincarnated back, after all this time inside the Tower, at the Day of Doom, and he is determined to get even stronger than he was before regressing.