A Hetalia: Axis Powers fanfiction series by Shadows in the Light of Day. It focuses on the Baltics, Belarus, and to a lesser extent Ukraine and Russia. The main series consists of ''Interference'', ''Latvia's Absence'', ''Insanity'', and ''Web of Delusions''; the oneshot ''Why Does He Hurt Us?'' takes place in the same universe but is not technically part of the series itself. ''After Insanity'' is a set of spin-off fics depicting how the characters deal with the results of everything that happened during the series.
Written in Blood, a crossover with the Hunger Games, could be considered a sequel, and it's best to read at least Web of Delusions before reading that.
Soviet Insanity provides examples of:
- Beware the Nice Ones: The entire series basically revolves around Estonia becoming murderously insane because of the abuse Russia has put him through.
- Break the Cutie: To almost everyone, especially Lithuania and Estonia.
- Covered with Scars: Even Ukraine ends up with a scar, and all of the Baltics are as physically broken as they are psychologically. By After Insanity, most of Lithuania's are from self-harming and suicide attempts.
- Downer Ending: While Web of Delusions does end with Lithuania finally being rescued, he's already suicidal, emotionally exhausted, and generally broken beyond repair; then, once he's out, he is rejected by Belarus. He... does not take it well.
- Hidden Depths: Everyone, really, and it's explicitly pointed out by Belarus on several occasions:"There is much more to me than my obsession with Russia and my annoyance with you!"
- Hope Spot: At the end of Insanity, the Soviets finally stand up to Russia, convince him to let them go, and play in the snow together while they make their plans. It doesn't last.
- Mind Rape: Russia does this deliberately to Estonia.
- Too Nice to Live: Everyone could have gotten out safely if Lithuania hadn't decided to go back for Russia.
- Unstoppable Rage: Estonia attempts to kill Russia and is only stopped by Lithuania stabbing him. Unfortunately, this just makes him even more susceptible to Russia's emotional abuse and makes his insanity worse.
- What Have I Done: multiple examples. In particular, Belarus when she stabs Lithuania and Russia once he realizes the extent of the psychological damage he has inflicted on his family.