MadCamel wrote:The Allied Detachment is fine. The real problem is that Strike Force Command cannot be taken outside of a Gladius Detachment alone.
This is not necessarily the case, and the argument around it is more of a
YMDC problem. The "non-Dataslate" Formation entries for each Decurion-style formation are in sort of a gray area as far as whether or not they can be added on outside of their parent formation. The relevant line is copy/pasted into the rules outlining each Decurion formation:
Note that you can also include any of the formations presented in this section as part of a Battle-forged army.
Which then goes onto list all the legal Formations that fit into the Decurion, including the non-Dataslate ones, such as the Command options. Realistically, the only difference between things like the non-Dataslate "Command" options and the more 'normal' Decurion Formations is that the non-Dataslate ones don't get free bonus special rules, so it's hardly a huge concern.
As far as this guy's fun games against his friend, he's probably fine.