There’s been a rule update to EDH, If a commander is in a graveyard or in exile and that card was put into that zone since the last time state-based actions were checked, it’s owner may put it into the command zone. If a commander would be put into its owner’s hand or library from anywhere, it’s owner may put it into the command zone instead. This replacement effect may apply more than once to the same event.
#TLDR If your commander dies you will get a death trigger and you can choose to@put it in the command zone after the trigger resolves. If for example Elenda, the Dusk Rose was your commander and she dies, she will generate the vampire tokens and you can opt to put her back in the command zone after.