Another example: the bloodclaw starhost :
Predatory Fighters: Saurus Warriors , Knights or Guard from the
Bloodclaw Starhost make one additional attack with their Powerful
Jaws and Stardrake Shields in the combat phase.
Strategic Mastery: The Oldblood, and any other Heroes from its
starhost that are within 20” in the hero phase, can use the command
abilities on their warscrolls even if they are not your general.
I'm the case of predatory fighter, this would remain active even if your oldblood is dead, but the strategic mastery would not work because you don't have an oldblood to measure off of anymore.