Luckily, this was nothing that others could spot, otherwise the issue would rise to whole new heights. But it was undeniable – Eiro had Holy Energy stuck inside of his body.
It was most likely a residue of infusing himself with it. Usually this sort of magic would simply fade away over time, but in this case, it apparently didn't. The Holy Energy reacted to Eiro's flesh in a different way, it being his bane. That probably explained why Eiro kept on feeling worse throughout the day, because he simply wasn't aware of what was going on within his own body. He wasn't particularly focused on it, after all.
'Now, that is not good.' Eiro thought to himself. Him using magic pulled the Holy Energy forward into his arms, and no matter what other magic he would now cast, the Holy Energy would probably be passively pulled out as well. The smoking and sizzling that came with it would be pretty hard to hide from others.