All Knives, all the time, regardless of Chapter.
Bolt Carbines are ****. If you are a Chapter where Assault Bolt weapons are your goto...You can still pick any other unit because Reivers are terrible and do not do what they say on the tin. And one of the big reasons for this is simply because they aren't Troops. They're Elites. Which means you compare them to Elites, and you compare them to other Factions' Elites.
"This is my Elites-slot unit, it can destroy bad Troops units that have already been damaged."
...Good...Job? I think?
So why have Reivers with Bolt Carbines when you already have Infiltrators?Building Infiltrators from the Shadowspear box...
Fixed. Reivers don't do the job. That's what makes them one of the worst units in the Codex.Reivers aregoodforshutting down ObSec and chasing weakened Troops off the boarddoing what any other unit could do, except worse at it
Just 'cause they do something, doesn't mean they're good at it.
Reivers, simply, are one of the worst implemented units in the Codex. And they were last edition, too. Releasing Infiltrators/Incursors, in the Troops slot, too, was their death knell.
Then you need Victrix Honour Guard...Which only come out of the Marneus Calgar box...Who would replace Guilliman.And Phobos HQ tend to be prime Melee charge targets to your opponents (with the exception of the Librarian)
That's because Death to the Traitors! comes out of the main Codex already.
Death to the Traitors; Re-roll to hit in the Fight phase vs. Heretic Astartes.
Vengeance for Calth; Ultramarines re-roll to hit and wound in the Fight phase vs. Word Bearers.
It works as a design choice.
It's just a bad design choice. Other Supplements have similar.
"It was designed to be bad, so it's fine."