the main character often seems unusually blank or numb in the face of horrible situations, but he always seems to be *mostly* aware of what's going on around him.
The villains are called Devils, and come from another world called Hell, but other than the names, there's little that connects them to christianity.
A major arc in part 2 revolves around a cult that worships the main character.
In new chapters, the main character notices that a character has recurrently shown up around him, and many panels show the character silently watching the main character and even making the MC uncomfortable with their presence. The main character asks them, "Are you stalking me?" to which the character answers "When you put it that way, you aren't exactly wrong", inferring acknowledgement that their behaviour is uncomfortable.
Yes and it's a pretty major plot point. It happens in the first chapter and kickstarts the whole plot. There's also a scene a couple of chapters later where someone believes their cat dies.
an adult is sexual towards a minor (however, debatable whether this is really pedophilia as the adult isn't actually attracted to said minor) and another adult is also sexual towards a minor (don't remember if there was attraction here) however stops themselves from doing so (although, they do offer to help the minor get with a DIFFERENT adult right after)
The main character is not assaulted, however he is a minor and an adult character does attempt to have sex with him while drunk, and jokes about how she wouldve gotten arrested once she is sober.
[SPOILERS]
The main character is fighting a devil that is the incarnation of darkness, so he sets himself on fire to “fight dark with light”. He is effectively immortal and regenerates forever, so he doesn’t die.
Par for the course. Limbs gets cut off multiple times, and while most of the time they are reattached due to characters' regeneration skills, there are two characters who lose their arms permanently.
A character is kicked in the nuts once early on during a fight. At one point the main characters captured an enemy and took turns kicking him in the testicles as revenge for killing their friend.
Chapter 13, a child unintentionally walks into a bullet storm. The body is not shown during or after.
Chapter 75, bulletstorm on child choir, you see it this time.
Chapter 76, same as 13.
not really as it's a manga with still images but some panels could surprise you? there is a few that could be potentially jarring when you suddenly see them but, not really
Characters often cut themselves to offer blood to devils for various purposes, one character can form weapons out of her blood so she makes incisions. In one scene many people commit suicide to give power to a devil so it will fight for them.
several major villains have bizarre and surreal powers that warp space, or change the rules of reality, but they are all treated as unambiguously real events that are actually happening.
One of the main characters has frequent panic attacks after a traumatic experience because she has PTSD, they aren’t shown in detail and you can’t hear anything like gasps for breath since it’s a manga.
In part 2, in the original japanese, one character calls another a slur. However, it is replaced with a less offensive equivalent in the english translation.
other comment is kinda lame - misgendering doesn't only affect trans people
in PART 2,
the main character is misgendered by a character who doesn't like him, and, atleast in the english translation, is called "chainsaw woman" as an insult
You can argue that the lesbian characters are misrepresented as their relationship is very sexual. In the context of the entire manga, though, it's not horrible, still sorta uncomfy though.
in PART 2,
an antagonistic character is misogynistic, and (i could be wrong as i don't know japanese, sorry if i am) even calls another character a slur in the original japanese text (in the english they don't)
said character also complains about how a male character acts "like a woman" and calls him a woman to mock him (idk if this counts. Just in case)
It’s technically not a relationship, but one of the adult(himeno) characters has a crush on minor(aki) which preassuming they have a huge age gap. 2 main characters Denji and Makima, Makima flirts with Denji despite Makima being older. Again, these characters aren’t in a relationship
the main antagonists are called Devils, and they come from a bizarre and horrible dimension called Hell, but there are very few specifically christian elements.
The protagonist has a goal of getting to touch a girl’s chest and frequently notices them, but quickly realizes it means nothing without an emotional connection
the main character is a masochist, and during a sex scene, a character asks "what if I crush your balls, will that get you in the mood", but it's ambiguous whether it actually happens.
Not quite, but this is similar. Just in case:
In PART 2,
A male character is ridiculed for "whining like a woman" and even called a woman to mock him for acting that way.
very early on, a character mentions having a terminal illness a single time, but he quickly acquire magical healing powers that completely negate it. it never comes up again.