You can include Astra Militarum units in your army, even though they do not have the Genestealer Cult Faction keyword. The combined points cost of such units you can include in your army is:
A Genestealer Cult model must be your Warlord, and Astra Militarum models from your army lose the Voice of Command ability if they have it. You cannot include units with any of the following keywords in your army using this rule: Aircraft; Commisar; Epic Hero; Militarum Tempestus; Ogryn; Ratling; Tech-Priest Enginseer; Ministorum Priest.
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