RPG games in space / futuristic.

Diablo is not a rpg, it's a-rpg at best. Try using https://steampeek.hu/ to start from something you know and see what gets recommended.

Why am I making a distinction? Because you probably don't wanna play Anachronox, FTL, Halycon 6, Starpoint Gemini... if you're looking for something like Diablo / Space Siege, you might have more fun playing Alien Swarm, Reactive drop, Warframe, ...

https://store.steampowered.com/app/527430/Warhammer_40000_Inquisitor__Martyr/ maybe?

Doubt there are many of them. INSOMNIA: The Ark and Colony Ship (still in EA) are the only fresh/decent examples I can recall.

Take a look at I am not a Monster: First Contact and see if you like this style.

Other good games that have something related to space (but noting with Diablo at all): Endless Space, Mini Gal4Xy, Borderlands: The Pre-Sequel, Oxygen Not Included, Tharsis, Cosmic Express, FTL, Gods Will Be Watching, Holy Potatoes! We’re in Space?! and Dungeon of the Endless.

Don't forget about the excellent. yet short, Outer Worlds.

The Alien Breed Trilogy

There are Diablo clones out there like Torchlight, Grim Dawn, Path of Exile, etc., but I just can't think of any that are set in space.

Killsquad could be pretty close to what you are looking for: https://store.steampowered.com/app/910490/Killsquad/

Hellgate: London was awesome back in the day (simply because much of the staff from Blizzard North started and moved to Flagship Studios). Like Diablo, Hellgate is an ARPG that is "set in a post-apocalyptic London in the year 2038," so it could technically be considered sci-fi.

You can get Hellgate on Steam for a decent price... but be aware since HanbitSoft re-released all the content into single player, parts of it are quite buggy since the online components were taken out.

I would say Elex can fit as rpg with scifi signs, maybe also Fallout or Technomancer, but I think these are a bit different games than Diablo.

Space Hack :)

Maybe this fits what you are looking for . https://store.steampowered.com/app/527430/Warhammer_40000_Inquisitor__Martyr/

Thanks for all ideas, guess there is not many of what i look for. Shame i can't get anyhow key for Space Siege for steam.