Battle Brothers

I was talking to a friend about the new Battle Brothers rule in the FAQ, and he said that Drukhari aren’t able to ally with Cradtworlds unless they’re Ynnari. But, I keep seeing Drukhari tournament lists with a Craftworld detachment and they don’t say they are Ynnari.

So, my question is, would I be able to legally play a Drukhari Battalion alongside a Craftworld Patrol detachment? Sorry in advance if this isn’t the right area to ask this question.

You can't play them in the same detachment but separate detachments is fine.

Yes, you can ally.

The new Battle Brothers rule means you that you can't unite DETACHMENTS under the keyword Aeldari, so you can't have Craftworlds, Drukhari or Harlequin in the same Detachment.
You CAN have them in seperate Detachments though, in the same Army.

And the army is still battle-forged if you do that?

Yes, it is.

Pre-FAQ you could have an Aeldari Detachment if you wanted who could have say a Farseer and Warlock in a Battalion with the rest of the list made up of Drukhari and Harlequins units. The Detachment wouldn't unlock Stratagems or get an Obsession / Craftworld Attribute, but would give you your choice of units from each book.

Post-FAQ each Detachment can only include one of Craftworlds / Drukhari / Harlequins, although you can still include a mix of Aeldari Detachments in an army.

It is a small tidy up, as most people would want Stratagems and Obsessions anyway, so wouldn't use an Aeldari Detachment after the Codex had dropped. Pre-Codex, you could gain some extra benefits from sneaking some Craftworlds units into the list.

Okay, so if I have a Drukhari Battalion detachment and a Craftworld Patrol detachment, would I be able to use the stratagems and obsessions from both books?

Yes.

Thanks for the help everyone. That really clears everything up.

Stratagems with the same name count as the same.
So you can't double up on fire and fade or lightning reflexes.
The deep strike strats are different names though. So you can use both.

We actually have five Stratagems in common by rules with Craftworld Eldar, but only two of them have the same name. A little thing to bear in mind if you have both sets of Stratagems.

Lightning-Fast Reactions and Fire and Fade are the same name.

The Stratagems with different names but the same rules other than what they target are:
Webway Strike = Webway Portal
Cloudstrike = Screaming Jets
Feigned Retreat = Cruel Deception