Twenty years later.
Grimm's experimental observation of Destructive Energy required him to repeatedly replenish the high-density gel block within the crystal vessel. The replenishment process was extremely time-consuming as the gel needed to solidify into its block state after sealing its liquid form into the vessel. As such, Grimm drew up several other plans on the side to improve his own strengths while the main operation went on.
Prior to Grimm's expedition into the Shadow Enigmatic World, he had amassed a number of ancient voodoo scrolls to aid the enhancement of his physique. This means that his research advancement on basic voodoo knowledge lagged far behind that of modern sorcerers.
As such, if Grimm did not devote more time and effort delving into voodoo knowledge, even his field of Intoxication Sorcery was at risk of ending there and then.