fluff/background ynarri question

I'm just getting back into the game and I have read a little bit about the Ynarri, I have a basic understanding of what they are and what they are trying to do from a background standpoint. As the title suggests This is probably more a fluff question but as far as building an army. Can I build an all Drukhari force that is aligned with the ynarri? Is there anything that should be included? I was thinking about a mainly Kabalite build.

At least one Ynari HQ is mandatory now, if I remmeber correctly.

But the rest of your army can be pure DE.
Would recommand Scourges and beasts

From an in game perspective, you must have a Ynnari warlord (Yvraine / Visarch / Yncarne) to play a Ynnari detachment. You could have a Drukhari force that is Ynnari aligned in the fluff, but wouldn't get to use their rules without the Ynnari warlord.

Craftworlds and Harlequins probably have better synergies with Ynnari rules than Drukhari, but I'm sure there are ways to make it work with lots of Kabalite infantry and Scourges.

Ok, thanks!

As I understand it, allying to Ynnari isn't just a case of being their and working for tehm. Its like a full religious conversion, and an adopting of their ideals. As such, those ideals change the way they interact with.......reality, I guess. It changes the ultimate fate of their soul.
That shift is represented in rules differently, but to get that effect you need one of the Ynnari characters.

However from a fluff perspective, it is easily possible for an entire Kabal to turn to Ynnari, and to continue operating as a Kabal uner the new philosophy.

do you lose battle forge if you bring ynnari with DE but make DE warlord?

In order to have any Ynnari your Warlord must be one of the Triumvirate.

Indeed. If your Warlord is not Ynnari, you can not have Ynnari.
That isn;t really even a case of losing Battle Forged. It just says no, you can't do it.