Amnesia?

Leon was taken aback by David's situation.

'Hmmph, and he tried to make me absorb that strange so-called energy after killing Evelyn!'

'Thankfully, I didn't do it. My body is much frail compared to David whose body has become so much tougher now...after the help from the old man.'

'If I was in so much pain, I would have died directly.'

The old man got a little anxious,

"This is too bad even if we help him, his strength would be fixed and won't be able to increase in the future!"

"Hurry, let's take him to my house."

"My wife has an ancient medicine that can at least stabilize him for now!"

If Elandor was here he would have laughed at David's stupid actions, unlike him who had the luck-devouring lotus which can devour and refine luck and the protagonist's opportunities into the purest form of energy to raise one's strength, David's approach toward Eve was much cruder and the energy he obtained was much less & full of impurities, enough to make one's foundation unstable.