The main character wears a school uniform with a short skirt for the entire series. Not sexual in any way.

In one scene the main character's shirt is unbuttoned, revealing her bra. Not sexual.

A support female character's buttocks are briefly glimpsed. Not sexual.

A minor plot element deals with two characters committing adultery, but it's only implied.

Two female support characters are dressed in skin-tight full body suits. In one scene one of the characters makes suggestive movements towards the other while lying on top of her.

Frequent and intense depictions of violence and destruction, but mostly happening between giant mecha. Not very gory or drawn out, but may be disturbing for some. Here are some examples:

Characters cough up blood on multiple occasions.

A soldier is strangled.

A support character's arm gets ripped off. The act itself is not shown, but we see an arm flying in the air with blood spray and the character lying on the ground with a large pool of blood.

A humanoid creature gets crushed by a metallic, clawish weapon, and we see blood gushing from between the fingers.

A character's body is fully pierced, and we see blood seeping from the wound.

Throughout the series soldiers get crushed, impaled or otherwise injured or killed along with their mecha. No details of the injuries are shown. We sometimes see brief, but plentiful blood spray.

Towards the end of the series there is a scene resembling the detonation of a nuclear weapon, though it is mostly conveyed through its aftermath and the character's reactions to it.

Infrequent mild language (depending on the translation): multiple uses of "bastard", "dammit" and such.

We see some characters drinking wine.

Occasional brief smoking.

In one episode the main character is clearly but briefly intoxicated, and it is implied she passes out.

As mentioned, the series features frequent and intense depictions of destruction. Mass killings are implied multiple times, though mostly mere aftermaths are shown, i.e. bloody bodies lying around, burning buildings etc.

The first episode's last third is particularly intense and conveys a heavy sense of danger and threat. Some might find the dragon in the first episode repulsive and disturbing.

Infrequent, but intense and surreal prophecy sequences: we see visions of massive destruction, death and distorted reality. In one such sequence the main character is standing on a field filled with bodies. Blood is raining from the sky, and we see a ghostly image of a support character who has been shot with multiple arrows sink slowly into a pond of blood.

One of the antagonists is clearly insane, sadistic, and takes joy in slaughter. His behavior and the reason behind his identity may be disturbing for some.

One scene shows a badly injured character screaming in agony and convulsing so hard he has to be tied down. In another scene it is implied his chest is about to burst.

Many of the character backstories are quite tragic, as many members of the cast have lost family, friends or both.

This series is fairly intense and features numerous and intense depictions of war and battle.