Reincarnated with a Fusion System

.[Fusing...]
The world gained mana, when and how that happened no one knew. But in the aftermath came the appearance of towers. Places where monsters rushed from in order to conquer humanity as it was known.
Yet that was not the end, as years later, after countless deaths and sacrifices peace was restored. Schools were made in order to educate the next generation of hunters, those that would climb the towers and save humanity a second time should it be needed.
[10%]
But that was for those who were talented, for the hundreds of thousands that had the grit and talent to be chosen and climb through the ranks.
[30%]
That was not me, a talentless reincarnate, one who had less mana than even a baby. Yet even so I still tried, thrived in my studies where in combat I could not.
[50%]
...
...
[100%]
[Welcome to the fusion system, a place where everything and anything can be fused. Your destiny is now your own. Take it and make history, fuse and create, for that is your purpose.]