Can Thousand Sons use units from Codex Space Marines?

[chapter master 454]

Simple possibly dumb question for you guys, are thousand sons allowed to use units from the Codex Chaos Space Marines or is there a reason they can't?

[WarriorFish]

Thousand Sons are their own codex - what is in the codex is what they get (FW aside). If you want units that are C:CSM only then you'll need to take an allied detachment I'm afraid (though you can still mark them as Tzeentchian), short of running unbound which I wouldn't recommend in most cases.

[Zodd1888]

With that said, talk to your opponent. Most people won't mind a game or two with an adjustment like that.

[CrystalSeer]

Allied detachment only: Thousand Sons have different faction keyword than Heretic Astartes. That said, allied detachments are really easy to do.

[Special Officer Doofy]

Allied detachment only: Thousand Sons have different faction keyword than Heretic Astartes. That said, allied detachments are really easy to do.

I'm sure what you meant was they have different <legion> faction keywords, because they both have Heretic Astartes faction keywords.

 

Chaos Space Marines codex says: The Death Guard, Thousand Sons and Fallen deviate significantly in terms of organisation and fighting styles. As a result, you cannot choose one of these keywords when determining which Legion a unit in this codex is from. The rules and abilities for the Death Guard and Thousand Sons Legions are detailed in their own codexes.