An LGBT character that is cheating on his wife with a man is threatened by the wife if the player tells her. A villain that is implied to be gay and a rapist is killed by the character.
One of the 3 tataus you can get is a spider, and some relics found across the island are labeled as "spider relics" though there aren't any actual spiders
The protagonist, Jason, will wake up from drug trips with Citra riding him several times. This is neither presented as a positive or negative thing, yet is still rape as Jason does not consent and would also not have been able to due to the drug influence.
In the promotional videos for Far Cry 3, someone is buried alive and can later be found in-game as a reference to the videos, earning the achievement "Say hi to the internet", This scene is also featured in the main poster for far cry 3, where you can see vaas sitting next to the head of someone who has seemingly been buried alive.
In the first mission, you can see people's hanging at Vaas' camp, on the game poster there are 2 people hanging in the back, and in a secret achievement you can get called 'Say hi to the internet' you can find the 2 hanging people at a certain location.
spoilers ———
It is canon that citra and vaas were in an abusive incestuous relationship but it's not shown in this game, only in the Vaas: Insanity DLC for Far Cry 6.