I've been thinking about and looking for this webtoon for quite some time, but i just can't seen to find it. It's about time travel where in the future there are some monsters, super human abilits and dungeons. The mc comes back to the past when things were normal as a baby then he makes some plans and kind of skip time until middle school, i think. Then he starts making money in some investiments with some blond dude that was his friend in the 'future'. It was remarkble because didn't seem to focus on the fiction stuff just on economy at some point. Sorry if there are any mistakes I'm not good in english