pretty sure the strength eaters need to be "alive" to eat
Shopkeep is interesting.... but i disagree that he "knows everything" (or is more plot reliant/strapped than deus), even if you ignore "joke stuff" like him calling MC charlie (despite him knowing that he would be selling to charlie and that MC and charlie would know each other), why does he only indirectly interact with "weak" people (aka no level 5s) despite multiple of his items directly involving/impacting them? (Shopkeep helping charlie indirectly pushed charlie towards leaving sin, the whole rune thing for henri) if he knows all, can go between the matieral and immaterial and can get anicent (sky/sea) parts, why arent zak/deus aware? Or does deus allow shopkeep to get away with stuff because deus knows its pushes MC towards what he wants? That doesnt explain why zak (pre injury/now) is allowing a third party to influnece stuff as heavily as he is
IMO shopkeep is something/one that "shouldnt exsist" rather than another very powerful "deus ex machina" it wouldnt really change much about his character the only thing it would really chnage is he doesnt interact with strong people because they are likely to know what/who he is and they might not allow him to keep doing what he is doing.
Whose the strongest person we have seen directly interact with him? Is it MC/Met/Charlie at level 3? Im pretty sure if you help henri MC only make a mention of shopkeep to him and even then henri seems like the most likely "strong person" to not care what shopkeep means/could represent