Ok I made a Nightmare deck consisting of Sargh lelena Estalt Vince orlock nistarock Pan Mawpin C Beast and Ashigaru anything I can do to improve it
Well there's tons of things to improve to that.
1. 10 characters in a deck? no
2. Weak low stars for t2? no
3. C Beast out of his clan as a fill up? no
Look around a bit more at T2 presets in the public presets and you should get an idea of how a T2 deck should look like.
This is what i run for t2 survivor http://www.urban-rivals.com/presets/?id_preset=1597618
French Revolution thats what I use
Nightmare and survivor T2 ... me too, I use http://www.urban-rivals.com/presets/?id_preset=1050246 a good starting point would be 2 clans and 1 Leader, and very few cards below 4 stars are seen in T2 survivor the only one i can think of off the top of my head is Uranus. 5*'s and powerful 4*'s is what its all about. I hope this helps and i wish you luck