Whenever Drana, the Last Bloodchief attacks, defending player chooses a nonlegendary creature card in your graveyard. You return that card to the battlefield with a +1/+1 counter on it. The creature is a Vampire in addition to its other types.
If Drana attacks a planeswalker, that planeswalker’s controller is the defending player.
The defending player chooses a card and you put it onto the battlefield all while Drana’s ability is resolving. No player may take actions in between those events.
Because all attackers are declared at the same time, the returned creature can’t attack during the same combat it returns, even if it has haste.
The returned creature remains a Vampire in addition to its other types even after Drana leaves the battlefield.