Some of the behaviour of King Garon and other major characters may be viewed as gaslighting as they intend to shift Corrins perception of themself and their actions.
No horses visibly die, but if an ally or enemy who rides a horse is defeated then their horse will be shown collapsing/falling while the rider is thrown off.
In both Conquest and Birthright, a dragon named Lilith will end up passing while sided with you. In Revelation, you and your team slay a godlike dragon.
In Conquest, the character Takumi will throw himself off the railing of the wall after battle. However, he was being possessed and had already been dead prior to the jump.
Niles does wear an eye patch (in the Japanese version, he says his eye was taken from him by an unworthy person) and Saizo has a scar along his eye, with the eyeball white with cataracts, but no eye violence is depicted.
The character Nyx is an adult woman who was cursed to look like a child. Her default outfit is very revealing. It is also possible for very young looking characters to wear revealing outfits.
In Birthright, Elise is accidentally killed by Xander, and Xander lets himself be killed by the player. Azura also evaporates into bubbles onscreen. I'm Conquest, Ryoma commits seppuku, and Takumi is killed as well. Azura vanishes as well, though not onscreen. In Revelation, all the main characters live to the end.
Azura, when a child. She was kidnapped from Nohr to live the rest of her life with the Hoshidan's.
She says that she loves living in Hoshido with her "adoptive" family since the Queen thinks/treats Azura, growing up, as a daughter.
There is a bath house in which the characters can spend time together while sitting in the water and being partially covered by swimwear or a towel. Building this bath house into the player base is completely optional.
In all game routes, King Garon is possessed. In Birthright and Conquest, Takumi will be possessed but it is more prevalent in Conquest. Takumi’s possession is also spoken about in Revelation. Also in Revelation, Gunter will be possessed.
In Birthright, the character Flora will set herself on fire out of guilt for attacking her former liege and sister.
In Conquest, the character Ryouma will commit seppuku after his defeat in order to help the player avoid killing him themselves.
The character Forrest is male and likes designing and wearing dresses. His father isn't thrilled about this, but there are no jokes and he later comes to accept his son. Completely avoidable.
In line with kid and parent death. There are only two LGBT characters, Niles and Rhajat. Niles is available for marriage with men and Rhajat for women. They can both die in specific gamemodes, as well as depending on the story path you take.
The player character, Corrin, can marry and produce children with any other character, including any of their adoptive siblings or "birth" siblings. There's a cop-out twist that reveals they're not actually related, but this is only revealed after you've already married them. Even if you don't marry them, at least one of them (your older sister, Camilla) acts overtly flirtatious and sexual with you, regardless. It's also possible for male Corrin to marry Azura, who turns out to be his first cousin.
There is sort of a happy ending. The game focuses on the hardships and loss obtaining said happy ending, which nullifies and makes it not so much a happy ending. Significant characters die in both Conquest and Birthright, while Revelation can be considered the true ending, with as little loss as possible.