There are scenes where the main characters forget to feed their fish or suggest experimenting to see if fish could survive a change in environment. It’s not super serious but happens to occur from the fish’s point of view.
The main character is physically abused by his mother. In later chapters, it is revealed that a different character was physically and sexually abused as a child.
spoilers//
it is heavily implied that the main character's elder brother is in love with him and he at the very least has some sort of sick fascination with him, though this is portrayed as a bad thing.
The manga has not been updated since 2017, and does not look like it will be continued. It is unconfirmed, but the 14th volume may be released soon. The place the story leaves off is not happy.
A female character tries to pass as a boy because she thinks the guy she has a crush on is gay, but that's as close as this series gets to having a trans character
At the end of the combined 1 and 2 volume collection, there is a picture of Ritsuka with an IV bag, and the needle in his arm is visible. The picture comes right after the extra story where he loses the charm Yuiko gave him, and is not necessary to the story
A character cuts herself with a razor to convince her girlfriend to stop self harming. Another characters is cut and stabbed many times in different scenes, both in battle, as part of "training", and when a name is carved into his neck. Various characters sustain minor-to-moderate severity cuts while fighting.
Yes, mostly in one of two ways. 1.) One of the main characters looks much older than she is (ie she has a large bust and is very tall for a 12 yo) and is very uncomfortable when this is remarked upon, which it is often. 2.) In this series, characters who still have their virginity have animal ears and tails, and lose them upon having sex for the first time. This visible marker of virginity is a cause of serious stress for some characters, and comes up often.
The answer to this question varies depending on what you consider cheating and what you consider a relationship. I said yes because loyalty and betrayal within deep/personal relationships are major themes.
***SPOILERS*** When Soubi is fighting the Zero pair, they break Soubi's arm. There is no visible blood or bone, and the arm does not look bent or twisted afterwards. Later, Soubi breaks Nisei's finger. Again, there is no visible blood or bone, and the only times we see the injury are after it has been treated and is bandaged.
There are a few scenes where underage characters drink, but not heavily. A child who is having trouble sleeping is given vodka without their knowledge by an adult to help them fall sleep.
While no one has an eating disorder, the main character's mother abuses him in part by strictly controlling what he eats in a way that could be triggering for some.
at least one character smokes and there was a small aside that may imply that a character may secretly be abusing or at least using drugs but nothing explicit and it is very, very easily missable even if you were looking for it
re the below: the main character is actually twelve, but other than that this is accurate, and i feel it is worth mentioning the elder character in question may be being manipulated into behaving this way on top of having been groomed and not knowing other ways to express affection.
in addition, there is a character later in the story who recounts (no graphic detail) being raped by a villain.
A character is burned alive, but nothing is shown. The main characters suffers from occasional nightmares where he sees his brother covered in gasoline and about to catch on fire.
spoilers// several characters can't feel pain and as a child one accidentally stabbed one of their eyes out. i don't recall it being graphic, only mentioned.
There is a very graphic scene where someone has a nail pushed through their hand. there are other scenes involving blood/gore but that is probably the most explicit.