what happens if your sub commanders die?

do you lose them?

i want to annihilate another planet that has my 3 sub commanders with the death star

In GW? You actually found subcommanders?

Last checked, they don't die. They come back. Wierd, huh?

It don't make sense, but its actually a sigh of relief in case they do something dumb like spawn by themselves on enemy heavy planet.

All the units and buildings that are built by that sub-commander will explode.
While you wont have the aid of the sub-commander and his minions for the rest of that round, youl still have that sub-commander to use afterwards as long as you keep that sub-commander as a tech

~Fun Fact, your commander can die, but you can still win the war if your sub-commanders win

While it doesn't make any sense, I really like this feature. Kinda neat to see your minions avenge you.

It makes perfect sense, they save the small data core from your commanders husk after the battle and build a glorious new commander and insert the date core there ^^

Or stay on the object I am halleying.
Or don't build anti-nuke and I can't protect both of us.
Or haley themself into the enemy.
Or land thier commander on the enemy planet and get him killed.
Or... well, as the saying goes: "Artificial Intelligence beats human stupidity by lenghts!"

You still loose the units of that commander for that combat (as far as I can tell AI is incapable to use team armies, so even if they have the same color they are different entities).
But the tech stays with you and he will spawn again next battle.

I found zero in a half dozen GW campaigns. After I unlocked the first additional loadout I find at least one on the free planets.