Welcome To Religion In Another World summary:

Past the dreams there is a special world, where monsters and demons fight for supremacy, it so happens those same monsters and demons are also the objects of cult for religions in the real world. A victory in the monster world, means the success of a religion in the real world.
Wahowaho is a new religion, aiming to the top, and while searching for their god they have summoned a clueless human boy.

Toda Yuu was visiting a fan convention with his sister, he was looking forward the event for his favourite game, a phone gacha game with deities, but once he fell asleep things started to change in the real world.