[GundamFan0083]

Spoiler for There is a short story but I've not done it yet:

If the "imposter" comment came across that way then that is a failure on my part.
I meant for it to seem as though Lelouch was in denial and simply refusig to believe that she ws still alive...thus calling the Red Dragon a liar.

Euhpie isn't aware of the reasons why Lelouch Geassed Nunnally.
She is only privy to the fact that HE DID Geass her and that was enough to anger Euhpie who feels that there is no good reason for Lelouch to have ever used his power on his full blooded sister Nunnally.

Yes, there is a sidestory about why Euphie's nightmares are so bad and why she's gone from sweet and innocent to a more mature, somewhat tarnished, individual.
She is more like Suzaku now than her former self in that she is still a very dear and good person on the inside, but the scars of what happened in S1 and R2 still haunt her so she's now developed a side of her personality that's akin to her older sister Cornelia.

I do have a side-story (which is Euhpie and Suzaku talking right before they show up to speak to Lelouch in Chapter 19) that explains the hell Euphie went through, how Enoch helped her remain sane, her training in the martial arts, and how she lived through getting shot by Lelouch.

The side-story is called Steps which has a dual meaning because Euphie and Suzaku are walking down the stairs towards Lelouch's private quarters while they discuss the events that led her to becoming the Red Dragon.

The story is not finished (although it's really short..about 4 pages long).
I was planning on posting it after I finish the main story.