I was searching a rule about primarch cards in an affiliated chaos army and I discovered that the rule saying "you must take the chaos legion first before taking the corresponding primarch" has been dropped.

This means you can choose Angron without taking the World Eaters Legion ? This rule was in the Sm/TL rules and I did not find it in 5.2 or Gold Chaos codex.

A deliberate choice or a bug ?

On french board, a player also told me that primarchs are not mentionned as "unique"...

I dont remember that rule. Can you provide a reference and a quote please.

The rule was in the Renegades supplement. On the french version of this book, it's on page 60 titled Primarchs, last paragraph, last sentence. It's just over the drawing of the duel with Horus and the Emperor of humanity.

If I translate it:

"If you pick a card of Primarch daemon, you'll be able to get his chaos space marines Legion in addition to other cards affiliated to a greater daemon".

So in fact the rule is that you cannot take the Legion without the Primarch. I'm not sure I really like that rule. It should be ok for scattered remnants of the World Eaters (insert preferred Legion name) to pop up in a battle somewhere without Angron (insert Primarch name here) having to hold their hand surely?

Actually, now looking at the English version, it was probably intended to be an army construction rule, but it is not worded very well. Given how much things have changed and particularly the introduction of new Legions I can't see the need to try and ressurrect this. Any dissenting viewpoints?

But could it be possible to pick a primarch in a affiliated army without picking the associated legion ?

You could according to the old rules. The rules said you needed the Primarch before buying the legion, not vice versa.

As long as they follow the army construction rules, and give him 3 minion detachments then yes, a Primarch could be present without their legion. I see this a lot.

OK, finally, a primarch is just a company card like any others

No problem for me to drop this old rule. Maybe just place a "unique" abillity to Primarches ? A real unique, not the "unique = 1 per 3000 points"

I'm jiggy with that. Anyone against?

no