My Best Friend is an Eldritch Horror (Light Novel) Vol. 2

Damien nearly ended the world. Now, his mistake might be the only thing that can save it. Good things come to those who wait. Damien Vale didn't, and he ended up bound to an Eldritch creature from beyond the reaches of space. It has lived since the dawn of time, seen the world born and destroyed countless times, and wants to be called Henry. Unusual companion or not, Damien was still determined to go to a mage college and study magic. He wants nothing more than to live a normal life as a researcher, but if Henry's true nature is revealed, he'll be killed. To top it all off, Damien's teacher is a madman from the front lines of war, his alcoholic dean suspects something is awry with his companion, and Blackmist might possibly be the worst school in history. Damien has to prevent the end of the world, but he isn't even sure he's going to make it through Year One at Blackmist.