Notes:

The scene comes from the manga series "Nidome no Yuusha".

The isekai'd hero defeats the Demon Lord, but is instantly betrayed by his companions and killed. However, it turns out everything up till now was in "Tutorial Mode" (because, realistically, how many of Us would be immediately slaughtered?) and so returns to the point of his summoning, retaining his memories and knowledge, if not his level. He then decides to take revenge on everyone that betrayed him, starting with the princess that summoned him here.

Don't worry, there's no r---! She just gets her mouth blown up, a message written on her back with a burning knife and then her throat scorched so she can't call for help! A family friendly torture, no child will have it's psyche shattered!

Soon, he gains an accomplice, the bunny girl in the meme, who was also betrayed by… s---, almost everyone in her life. As her first act of vengeance, she poisons her fellow prisoners and the slave trader with food that turns them into goblins and then kills them. F-----' elaborate, ain't it.

In short, it's a revenge fantasy. Though the scene, where the hero and the bunny girl discuss on how to most effectively use magic eating maggots on their enemies is disturbing… because it's also hecking adorable. It's weird.