I currently have a level 24 Pyromancer and level 14 Cleric, and I’ve noticed that while all my other stats stay the same, the INT stat seems to increase itself over time. My Pyromancer has gained 11 free points in INT, and my cleric has gained 2. I’ve double-checked my equipment and am certain that these points are just magically appearing.
What’s going on? 
I’m beginning to keep track of this, so far it seems like certain levels will give you 2 INT even though you’ve only clicked once and used 1 status points. These levels will give you 2 Magic attack points. Its easy to miss it because it happens this way:
Before level: INT 19
Level up: INT 19 + (click once)
Preview: INT 20, Magic attack +2 Max/Min
Result: INT 21, Magic attack +2 Max/Min
My second wiz is still low level so I haven’t been able to tell a pattern.
Also each statue Zemnya gives 1 additional stat point.
If it`s similar to ragnarok, you gain extra points for free automaticaly put into the stat depending on your class. So for example swordsman gain some STR every few levels, mages would game a INT every few levels. This is specific to your class.