Nina will be pulling triple duty, as Katherine, Elena, And Amara will all be in the same scene
What do you think Katherine is now? She was dead for a few seconds before you could hear her heart start beating again.
Is She Immortal?
Did Silas Drain all the Cure from her?
Could Nadia have fed her some of her blood, and she's in transisition? and is going to be a vampire again?
Or is she still human?