The second was using items.
The reason for denying this option was simple.
He had no money, at least not currently.
The third was engraving energy runes through runic words.
This was mainly a technical skill.
Although some materials for the runes were quite expensive, but compared to buying items, they were still relatively affordable.
Given Riley's current financial situation, he could manage to afford them.
Engraving energy runes mainly tested one's technique and needed to be done in one go.
Besides the precision in engraving, each stroke needed to be imbued with the same amount of mental energy.
Uneven mental energy would lead to an imbalance in the energy structure of the runes and ultimately resulting in failure.
In simple terms, this mental energy usage involves activating the Beast Tamer Codex within the brain domain.