I read a book about a boy that at a young age has to enter a tower and follow a series of puzzles / challenges that will ultimately allow him to discover his magic in form of a symbol engraved somewhere on his body.
These towers (6 or 7 of them) are spread out through the land and controlled by Gods. Story is if you get to top of each tower you get godlike powers
While during his trial he frees some prisoners and witnesses one of the gods fighting a stranger/prisoner. He then gets his symbol and then leaves tower. After that he attends a school of sorts where he learns to use his magic. He has I think, an ability to create items an imbue them with magical properties.
The book has a D&D theme to it with his party of friends etc. that are like a rogue, paladin, healer etc.
I cannot remember name or author as I lent it from the Kindle store and cannot find a record of it. I thought I had bought it, but I guess not.