Why is there then a program called GD Defiler?

You can play your characters online and offline. The so called games that you “join just like Diablo 2”. Isn’t server based. Let’s call them rooms, I create a room. When/if I leave the room, the room is not joinable anymore.
Bc I’m the host

Grim Dawn sucks online. As others have stated, there is nothing that stops an 8 year old from giving himself best items. You can play legit but since it isn't like closed bnet d2/current d2r. Pointless.

You can add your support for this here
https://forums.d2jsp.org/topic.php?t=72625318&f=258