What are YouTubers using to spawn in NPCs outside of their usual locations?

[TreshMek]

Seen here, here, and here.

 

All I want to know is what software and/or tools they are using to spawn them outside of their typical spawn locations. They also seem to be able to control who they are willing to fight and also when to enable their aggression.

[Happybara]

Not sure if you worked this out already but this mod may help: https://www.nexusmods.com/eldenring/mods/48