Attached Deployment
(Rule)Description: Models with the Attached Deployment special rule are not deployed as normal nor do they act independently on the battlefield. Instead, when deploying a Detachment during deployment, a player may assign one or more models with this special rule to that Detachment, so long as the two are the same Detachment type. For the remainder of the battle, the model counts as a part of the Detachment it is attach to and cannot leave it for any reason.
If, for whatever reason, a model with the Attached Deployment special rule cannot be assigned to a friendly Detachment during deployment (e.g., due to no Detachment of the same type in the same Formation) then it cannot be deployed and counts as destroyed.