Let's start with Ankaur Maro's list building passive ability:

Forbidden Lore of the Shadow Council
You army can include 1 non-unique unit from any other faction.
After setup, that unit receives 2 blight tokens.

Reading the rules implies we would need to take Waiqar or Neutral upgrades on the non-waiqar units granted by Maro.

We have our own Siege units, we have ranged units, cheap infantry that can regen and we are getting cavalry soon as well so what do Waiqar want from another faction?

Example:

The idea that first comes to mind is Latari battle cats with Combat Ingenuity.
They have a built in "double-surge to add a hit" result to the roll. With Combat Ingenuity this becomes a "single surge to add a hit"ability that you can use multiple times in an attack.
On Blue Dice, this gives them 6 sides with a single hit and 2 sides with a double-hit.
On Red Dice , this gives them 3 sides with a single hit and 2 sides with a double-hit.

For their cheap price, this is pretty good. You could take them at 36 points for 4 trays as a great flanker unit.
Unfortunately they don't have a skill modifier to spit those 2 blights at the enemy via War Crier after moving - that's a shame.

What other good combos can you come up with to use with Maro's passive?

I'm excited to bring flesh rippers and death knights in a mobile army with maro at the head. Flesh rippers seem to function fairly well out of faction, like rune golems, so adding them to undead seems enjoyable and should fit in thematically.

Since the current interpretation is your army's faction for unique upgrades, anything he takes will have Waiqar-only cards rather than their normal faction. Until faq'd otherwise that is (which i honestly kind of expect).

Spearmen with a Necromancer so they can regenerate powerful? nah. funny? hell yeah.

With only undead upgrades the flesh rippers unique slot will be useless

6 minutes ago, Klaxas said:

With only undead upgrades the flesh rippers unique slot will be useless

Any unit with a unique upgrade slot will lose that, and gain two blight.

On 7/8/2017 at 1:18 PM, Klaxas said:

With only undead upgrades the flesh rippers unique slot will be useless

Unless the unique upgrade associated with the unit isn't faction specific.

On 7/10/2017 at 9:08 PM, Orcdruid said:

Unless the unique upgrade associated with the unit isn't faction specific.

All uniques are designed to be used with 1 unit so i doubt we will see a generic unique untill we get generic units.

10 hours ago, Klaxas said:

All uniques are designed to be used with 1 unit so i doubt we will see a generic unique untill we get generic units.

The flesh ripper unique can be flesh ripper only without being Uthuk Y'llan faction.

30 minutes ago, Orcdruid said:

The flesh ripper unique can be flesh ripper only without being Uthuk Y'llan faction.

It could be, but the precedent so far is that all unique upgrades are faction-specific.

Ran Maro today with Fprtunas Die and Violent Forces. Being able to 1-shot rune golems is very, very nice.

I think it's ok that we can't use the unique of the others faction unit. Ankaur wouldn't get a specific type of the unit (represented through the unique upgrade). He just gets a standard version. Which seems to be great in lore context.

And with the Waiqar upgrades it gets a more undead feeling. And what is great for the budget: you can buy one unit less for Waiqar if u have already a second army.

Painting up my Maro now. What are people using for Shadow-council now that more stuff is around?

My go-to is 2x2 Spearmen with War Crier to set up terrifying mortal strike onslaughts from Carrion Lancers by sending the blight shortly before the Carrion Lancers activate. So far I've only tried this in the same army as a group of Reanimates, but I think Death Knights would fit better. Haven't tried any of the new out-of-faction units yet. I'm just amazed every time I run the 2x2 Spearmen how much easier they are to work with than Reanimates, which is nice to shake things up every now and then.