In anticipation of tomorrow's miniatures delivery, which is the only thing happening, I'm up late working on a some crew lists. Backstab off of Conflux of Tyranny grabbed my interest, as no one seems to be paying attention to it. Here are my thoughts on the matter:
We start Lucius with Mysterious Emissary and Conflux of Tyranny for Backstab. Backstab wants Lucius to activate late in the turn, and encourages draining your opponent's hand with it's trigger. Fortunately, that 10ss Emissary makes Changelings to help with that activation control, and it is my experience that Changelings are great hand sappers.
Continuing with activation priority, let's bring in Candy with Depression and Fears Given Form to harrass models Lucius isn't focusing on, like scheme runners, which prompts/wails the opponent into activating the models we want.
Following up for Depression's Melancholy, Doppleganger is always a favorite, and Mr. Tannen comes with a cheat tax (remember that Backstab Trigger), both with the ever useful Thousand Faces.
Since we'll be keeping Mr. Tannen and numerous Changelings close at hand, we can improve their survivability with The Scribe and Useless Duplications on Lucius. With Lucius heading into the thick of it, and with all these Mimics running around Surprisingly Loyal finds use here. Speaking of survivability, a Guild Lawyer would help keep the heat off with Impassioned Defense.
With 4ss left, that's a Changeling to start, or Secret Assets and 2ss extra. Suppose it depends. You could also trade out the Lawyer for a Performer to Lure and inspire a Changeling to Nature Reclaims All something in the face for more hand sapping.
In either case, enjoy your Stabby Lucius.