Responses
It was already stated that the blood thing was the mission.
They are investigating separately each place that can be the nest of those who provide blood to Undertaker.
And yes, the blood is (mostly) for Ciel's body, to keep him alive. But they only need Polaris blood for him
Haih... The blood again? This Baron really had been play by the Undertaker for good. He want to revive back his family. What a sick psycho. I think the Undertaker will used the blood for Ciel's brother