oh great, didn't realize Nanatsu no Taizai had a forum on mangahelpers !

Melodias being affected by that jewel reminded me of when we saw how they're mass producing new Holy Knights, by what seemed illegal, making weak potentials drink demon blood, and then produce more putent Holy Knights from that.

So the question is, what would happen if an already strong person, like Melodias perhaps, drank demon blood? Would he be far stronger than any other, because of his base skills?
Also an alternative possible scenario could be that he drank special demon blood, which is very rare.

Just reflecting here, but it would make sense, given that we saw failed Holy Knights drink demon blood earlier, in order to get stronger.