Fanfic idea
The mc or the person that is reincarnating to a parallel version of himself in one of the parallel worlds in that world towers suddenly appeared in every country and monsters came out of the towers then suddenly people called awakener who have gained powers and battle against monsters who came out of the tower and to prevent that people started climbing the tower and they were called climbers not hunters since they don't climb outside the tower, and the mc gets reincarnated in that world as a normal climber not a climber who entered the tower to prevent monsters from killing more innocent but the mc was also a climber well not the climber who climed the towers and clear it but a mountain climber, and the mc recieves a system and system that lets him summon everything that is scp and the foundation sites or the mc just gains the power of scp's, and to make it all better and not boring why not add some hunter type of thing from manwha's so why not being invaded being invaded by a fantasy world but thats kinda boring and to make that not boring why not add also being invaded by higher/lower dimensional planes. The towers have one tower master as its boss but its not a godlike being it could be just an demi-god as its highest in the towers and the lowest is just a normal boss capable of erasing a city block. And the invaders from other dimension and worlds range from Higher technological world, Immortal type of world, western type of world, and a world that has higher lifeforms that have obtained superpowers and other type of fantasy that you know. And in the invaders world there may be one god to one world or many since immortal world is here and its kinda huge there are probably many more than a thousand. And to also make it more interesting before everything happened in that world it got invaded by aliens because the humans have reached type 1 civilization and due to that aliens in the galaxy noticed it and became afraid and so they have come to earth and have ravaged and killed 70% of the population in the world and due to that and the damaged environment they have declined by serveral eras and so history repeates itself as they got invaded again not by aliens but from towers and other worlds and different dimensions but the world can't handle higher dimensional entities and even the universe cannot hold one higher dimensional entity so they will get rejected by the universe but it cannot do that for long as it cannot hold the information of a higher dimensional entity and so everytime the world got invaded by higher dimensional entities the world elevated to a higher dimension.