We would need to see your roster to help. There are a few options on dealing with her but the easiest way involves taking down the clones before they even get a chance. 

Best to learn what works with your lineup and manual until you are 100 percent confident you can run your team auto. 

Dark Fae is one of those tasks that feels impossible unto to solve it once then everything falls into place and you wonder to yourself was it always this easy?

Remember that it's a mirror match - but one where you always go first. As a result it's honestly one of the easiest fights in DT - you just need to build your team properly.

By far the easiest way to do it, is to make sure that your fastest champ is a hard-CC champ, or that your fastest champ is a TM boost and your 2nd fastest is fast enough to not be cut in. Make sure you don't use your CC move on the 2nd wave, and then just start the boss fight with your hard-CC. Stun tends to be the best choice, followed by freeze. True fear is also a valid option, though it tends to be a bit more random. Provoke I'd probably avoid, as even though you do CC the other team, chances are your provoker will end up dying, and then things can go badly.