Caroline

Casting spoiler for the actor playing "Berlin". You can catch a glimpse of him at 0:15 in the promo video above.

I don't think so. He said he'd known Sam all of Lizzie's life and 'most of' his own.

I hope it's Red's wife.

Yes, she knows he adopted her.

A dreadful episode mostly because for once Spader himself was 'off'. He seemed to be channeling his Boston Legal character, Alan Shore. Also, the 'Gaymond' scene? Awkward. But why was Madeline really stood up by Red in Florence? Perhaps because it must have been round about the time Lizzie got hitched to Tom?

Super paranoid and super broken. He might be trying to rebuild and redeem himself through Liz. "If anyone can give me a second chance, it's you." She has to be the key to some grand conspiracy which he's trying to uncover and in the meantime, he can protect her like he couldn't protect his own family.

I didn't recognise her!

I think they've made it clear that Red doesn't know what happened to his family, which sort of means Elizabeth can't be his daughter. She's also asked him, he said 'No'. And in the latest episode ("Ivan") he told her he's never lied to her. There's also one of the episode's 'Beyond the Blacklist' videos where the matter is discussed and both cast and crew say 'we've now answered the question'.