If you'd like to avoid any of the smorgasbord of content warnings in JJK, or just yell at me about how I'm doing, comments are screened.
so, those content warnings...
▸ Body horror, gore, and cannibalism: Body horror is JJK's bread and butter. People being maimed or transformed into hideous monstrosities is commonplace. Cannibalism mostly comes up in the context of eating fingers (sometimes voluntary, sometimes by force) to absorb or transfer power; at Megumi's current canon point, it's less likely to come up unless you get him talking about his bestie, but he does get in on that action eventually himself.
▸ Child abuse, neglect/abandonment, and human trafficking: Megumi's father disappeared when he was young; Megumi believes this was just abandonment, although his father is in fact dead. His step-mother also disappeared, and this one isn't detailed, but probably actually was abandonment. His father made arrangements to sell him back to the rest of the family for money, although the sale didn't go through. Said family are shitheads with a bad track record of abuse and misogyny; Megumi probably wouldn't have been on the bad end of this, but the only family member he's close with bore the brunt of it. All of it's not likely to come up unless CR gets very close, though.
▸ Suicidal tendencies: Not so much an actual desire to die as placing a lack of value on his own life versus the greater good, but Megumi does have an unfortunate tendency to jump to his tacnuke of a final move when his back is to the wall. At his current canon point, though, he has been made aware of this as a problem and is working on it. It gets better. (Unless he canon updates, in which case it will absolutely get worse before it gets better.)