Frequent abundant cleavage and scantily clad women.

In the entertainment district arc, there are conversations involving prostitutes.

Male characters bathe nude with bare chests shown, and females bathing show side boob/cleavage/buttocks. Sensitive bits obscured by steam or bubbles.

A girl runs down the stairs and her breasts bounce played for comedic effect.

Theres a scene where a girl is taking a bath, her full body is shown, but everything is covered.

Demons get their heads chop off pretty often either by the protagonist or demon slaying organization. however with the type of sword tanjiro uses, all you see is animated water slashing the head. no extreme gore.

Both humans and demons die. Some scenes involve the heads of demons being slashed but because of the shows animation its not gory. When the sun comes out the demons evaporate into thin air.

Many Bloody decapitations of demons.

An eye appears on the ground with blood behind it.

It is very common per episode for there to be blood and violence, however since its animated its about as bad as your average superhero movie.

The Natagumo Mountain Arc is the scariest arc in season one. Minor characters die and a characters hand appears with a gruesome spider bite on it several times.

The last episode contains violence as demons get destroyed with some bloodshed.

it is very typical for episodes to have a lot of sword fighting and bloody deaths. It is not the worst but definitely could make some young viewers uncomfy.

One demon uses threads to shred a demon slayer into a bunch of pieces

A demon kills a woman in a non-violent way, but it's very gory since the woman's cells start pumping and get destroyed (we get some close-ups on the face during that), turning her into a blob that melts into the ground. (personal opinion: it is still gory, as the demon pushes his finger into her forehead)

Often bloody decapitations and severing limbs. But the impact and circumstances of the action lowers it's tone. Some includes hands rapidly growing out of a humanoid body, squeezing it's head until it bursts, or a human body shredded to pieces with a piece of thread. Lots of blood, but minimum gore shown.

In one episode demon explodes in blood. After that you see her clothes on the ground and it's blood and gore all around it.

A demon, with her powers, wrecks several houses, causing large chaos. A man got his right arm cut clean(Only blood is seen in the area of injury) and lots of bloody scenes with some people lying dead as their partners scream in horror with blood on their faces.

A young demon girl uses her herself as shield to save her brother leading to being slashed brutally, a lot of gore and blood is shown.

Some scenes with demon regenerating their bloody heads, it's really graphical

A main character's head is almost crushed by a demon, his face was shown with lots of blood pouring out of his mouth

A man cuts himself so that he could use his own blood to tempt a demon girl into attacking him

A boy's family is slaughtered by a demon, his family was shown laying dead in the ground, a lot of blood was seen.

A scene with demon girl stomping another demon to the ground with her leg penetrating inside the other demon's back (her legs where filled with blood as she removed it from the other demon's back)

A demon's face is burned up with her eye ball popping out, this may look disturbing for some viewers.

In a backstory, we see someone getting his entire arm Dismembered by demon after trying to save his own brother, in fact that one scene is one of the darkest , bloodiest and goriest scenes of the entire anime

A swordsmith is sucked into a vase and crushed, screaming and crunching noises are heard.

Maggots eat a childs dead body in one scene.

Demons look pretty much like humans in most instances, so the gore is more impactful.

A demon has arms stab her stomach and mouth from inside, then the one from her mouth grabs her head and crushes it.

Shit and bastard are used sparingly alongside lesser profanity like ass and crap.

Some demons resemble spiders, which could be upsetting to those with a fear of spiders.