There are three important system parts in this world.
The Soul Core.
The gate. (The Mark)
Mana.
The Soul Core is something that is formed inside a human along with a mark. It is very vital for one to activate a Mark.
Both a mark and Soul core are formed naturally In a human accordingly to a milestone in age, (Birth, teenage, Adult-hood, middle ages(145,although adult hood has been 18 to 21 the aspect of being middle aged or old is very different from normal) and death.)
The Gate or The Mark acts as both a gate way and also the power release, by using the soul core energy one can activate the mark and accordingly use the powers given to them through it.
There are Four ranks for a mark.
Solidified. (limitations are added to innovating skills)
Described. (Misleading to an extent, lesser limitation to innovating skills)
Abstract. (Close to no limitations to innovation and let's one have more concept powers)
Vague. (Innovation is limitless, so are the concepts the only limit is your mind)
Mana is still very important in this world, for one to actually use their mark, they have to first open the gate part of the mark, to do so one needs to converge mana into the mark.
Mana is also very versatile in uses as it acts as a catalyst and Inhibitor but instead of only working as such on chemicals and reactions it works on everything as a whole, humanity's lifespan has sufficiently been increased by a long shot due to it's Inhibitor effect towards aging as well. (Mana is a bit too complex so I think you should just read the novel to get a better understanding.)
Those that awaken soul cores are called thinkers or philosophers.
Deeper Functioning...
One is needed to learn how to divert the soul energy in them towards the mark to activate it whilst also using the mana in the air to let the activated mark's power to come out, hence a mark needs two different energy sources to work.
Once a mark is formed, there is a need to form concepts regarding the mark, such as 'moving water' with that concept one can create a number of abilities on their own, it can be anything. as long as it follows the concept and doesn't clash with the mark description. Most of the time pure concepts are only formable at Abstract and lesser at Described ranks.