The system had four ways of categorizing skills. The first method was through skill books, which are dropped by demonic beasts once you kill them. This is purely a random process that depends on chance, because monsters can drop many things besides skill books, such as items, scrolls, ores, etc.
Modus had ordered Adelda to remove this aspect from every kill that Will made. Apparently, Modus said that this difficulty will 'temper' the boy and make him stronger. He also ordered her to make the boy's map and information options inaccessible. He made her modify the system around Will quite a bit, and often to make his battles more realistic and bloody.
One can try and emulate a skill from a skill book, if you do it successfully, you gain the skill permanently and the system will reward you,
