Eradicated Realm

One of the many alternate dimensions (or "Realms") connected by Nihilitree

This Realm was completely destroyed, everything but the world itself annihilated a different way
Very little is left, but the identifiable remains line up with the buildings and locations found in the Primary Realm

Science fantasy

Enigmatico received Riftmaster's Gift shortly before the Smyth family moved into town, and David ended up getting it. He used his new power to fight back against his father, who was abusive towards him at the time, and David accidentally ended up killing his father. Feeling a bit of regret, he decided to get back at the people who gave him the power, and he demolished Enigmatico. Starting to be corrupted by power, he ended up going back to his new hometown and ruined it. In doing so, he also killed two of his three new friends. He hoped to make it up to the one who survived, but she was scared of him and decided to stay away from him. David went mad and killed off everyone else except for her, but that just made him worse in her eyes and she ended her own life. Once he realized there was nobody left, he broke free of the corruption and gave himself a new name to distance himself from the person he once was. Starting to succumb to boredom, he started playing around with his powers, and he found a way to visit other worlds that appeared identical to his own. The corruption returned as he jumped in

(may be updated)

David got the power to fight back against his abusive father, went corrupt with said power, and ended up killing everyone

Same as our own

Magic does not naturally occur here

None left