Reincarnated As The Villainess's Best Friend

[WARNING][Mature content, erotic descriptions by a slightly perverted MC][All characters depicted are above the age of 18]**********My world ended in chaos, and I died trying to save it.I was Drey Belford, the most powerful mage in the world, but even I couldn't stop the evil villainess from destroying it.Now… I’ve woken up. Fifteen years in the past. And somehow, I’m not me anymore. I’ve been reincarnated as Rin Stormborn, son of a high noble...Best friend to the girl who destroyed everything.Armed with all my memories from my previous life, I’ve been given one last chance to change the future. All I have to do is survive magic school, navigate through dangerous noble politics, and keep my best friend from starting a world-ending apocalypse.Seems pretty easy. What could possibly go wrong?