Just if anyone is interested, I'm selling (I guess "trading" is a better word) a Shadow Cygnus core for 100 Purple powders. I can do 30%+ drop rate with cores.
I have tried killing the shadow empress in the past, but I can't do it because of my lack of damage on the last 10% HP. So the core has been sitting there for quite some time. (I got it from a mob)
Just with Familiar/Easter buff, 30% core drop and Greed pendant you can get between
Double the amount if you want to do it in a 2xdrop event or if you use a 2drop card.
You can give me a PM if you are interested.
Thanks for reading :)
EDIT: No longer have it. n_n