>>48572265I won't pretend to be an expert on Legatus lore (as a matter of fact, I willingly dodged every piece of content regarding his lore) but cyborgs are just regular ol human beings with cybernetic enhancements. Which on Fulgur's case seems to only be his extremities (but he probably has them in other places as well) so getting, for example, a stomach ache or a flu would be perfectly feasible.
You are probably confusing Cyborgs with Androids, who are way more mechanical (might not even have human bits on them) and less vulnerable to the weaknesses of the human organism.