Characters who either had very brutal deaths or had a very agonizing experience, however it was absolutely deserved

William Afton (FNaF) experiencing a Springlock Failure (Afton killed at least 6 children so he could study remnant and was horribly abusive to his own children)

Sentinel “Prime” (Transformers One) being ripped in half by Megatron (Sentinel killed all of the Primes and then later enslaved an entire generation so he could live like a King)