The main character gets put in another world that has all the mythical races as well as a medieval setting of magic and swords. Our main character has a system that allows them to check in every day to acquire an item from earth or a skill that can come from any time period. It can be from the past, present, or future.
The items and skills that he gets are not magical or anything in nature just the normal mortal stuff here on earth. But he uses the mana from this new world to improve upon the techniques he requires instead of outright having them already upgraded.