Q: Can units that are Battle Brothers embark in each other’s Transport vehicles during deployment?

A: No.

I want to preface this post by saying, I'm not one to mince or twist rules to try and get some sort of benefit out of my armies that simply isn't really there. We all know that guy right? I'm not that guy. Generally I tend to rule on the side of caution when examining how units, specifically formations with odd rules, interact with other pieces of an army. With that said, there has been speculation running rampant over the past week since Angel's Blade was released on the Archangels Orbital Intervention Force specifically how it relates to embarking on drop pods to gain a first turn assault. There are essentially two camps here. You either identify as an ITC player, or some other accepted set of rules separate from the GW Draft FAQ, or you do in fact identify as a player using the GW Draft FAQ. This is important because the issue is quite easily nipped in the bud if you're using the GW Draft FAQ; the answer is no, Terminators from the Archangels Orbital Intervention Force cannot embark on drop pods from say a Flesh Tearers Strike Force.The way Detachments and Allies work make this clear. A Blood Angels army that includes multiple Detachments or Formations uses the Allies chart in the main rulebook (page 126) to identify their level of alliance. In the case above, where you have the Flesh Tearers Strike Force (aka Seth's Taxi Service), and the Archangels Orbital Intervention Force (hereafter AOIF in this post), these are two separate Detachments in an army and thus use the Allies matrix to denote their level of alliance as Battle Brothers. This is where the GW Draft FAQ comes in.In May of 2016, Games Workshop, via their official Facebook page, released a series of FAQ and errata for 40k. In the first one released, the FAQ for the main rulebook, one of the questions asked is Note that Battle Brothers allies may not necessarily ever embark into each other's transports, they simply aren't allowed to start the game in them. Being that the drop pods in this scenario would be purchased from a Combined Arms Detachment (CAD) or a Flesh Tearers Strike Force, a separate detachment from AOIF and thus Battle Brothers with them, the Terminators in the formation could not embark on the drop pods to gain the turn 1 assault, as they cannot start the game embarked on them based on this wording. Many will make the argument that they are from the same faction so it shouldn't matter. That would be incorrect. It does indeed matter as their level of alliance according to the Allies Matrix is Battle Brothers when in separate detachments.Problem solved right?Not so fast. Many people (myself included) play ITC rules, whichBattle Brothers to begin the game in each other's transports. In this scenario, the AOIF could indeed use drop pods purchased as Fast Attack choices in another Detachment to carry out a turn 1 assault.First, let's look at the Archangels Orbital Intervention Force Special Rules and RestrictionsAbove, under Restrictions it simply says "none."The main special rule we're looking at here is. As you can see there are some key phrases here. First, all models must be placed in Deep Strike Reserve. When you make a reserve roll for the formation you make a single roll and all models enter play. It is my belief that the intent here was this ruling was specifically meant solely for the units in the Formation. That being said, nothing really restricts you from putting them in a Drop Pod from another Blood Angels Detachment in ITC rules.Drop Pods have a special rule which requires that they, and the unit embarked upon them, be placed in Deep Strike Reserve. Terminators don't have Drop Pods as Dedicated Transports for their unit, however nothing restricts them from embarking upon a Drop Pod taken as part of a Fast Attack choice in a Detachment of Blood Angels in ITC rules.So, we have two conditions that are met here; the Terminators are held in Deep Strike Reserve and are embarked upon Drop Pods from another detachment which also arrive from Deep Strike Reserve. There is nothing in the Formation restrictions or special rules that prevents this.The only requirement for reserve rolls is when you need to make them. In the case of putting the Terminators in pods, if the pods are designated to be able to come in turn one (half of total pods rounded up in your army) then there is no reserve roll needed. The formation doesn't require a reserve roll, it just states that when you take one, you make a single roll for all the units and they all come in.In order to get the Terminators from AOIF down in pods on turn 1, where their other special rule will then trigger allowing a charge, you will need at least 5 total drop pods in your entire army. The other 2 can be empty as well, or be dedicated transports for other units, it really doesn't matter. You need at least 5 to make it work. That means you have 3 that enter play turn 1 via the Drop Pod special rules, which can be those with the Terminators from AOIF embarked, thus allowing a turn 1 charge with the Formation.Yes, it seems sketchy at first, and likely NOT the intent GW had when they made this formation. Then again, they might not have clarified it simply because the Draft FAQ clears it up with no need for a clarification. In ITC events, and others like it where the Draft FAQ isn't currently in use for organized play, the water is muddied. In those cases, there is no reason you couldn't do this. Don't expect it to last much longer though, so if you plan on using this in ITC, until they make a ruling on it specifically, or adopt the GW FAQ you are free to use this method to gain a turn 1 charge with the Archangels Orbital Intervention Force.