Should I build Acasis or Hraesvelg?

I just pulled both of these guys, I can auto GB10 but not great yet just 6ed Bernard to help there, just waiting on lvl up now and only DB7. But now I just pulled both of these mons and I have enough essence to awaken one without much farming(some mid magic is needed) but are either worth building? I search and saw the Acasis is good for GB10 but not much else and can't seem to find much on Hraesvelg. Some advice would be helpful, I'm f2p so not too many other units to choose from yet. I know I have to farm giants more before I get good enough runes to do dragons, so which would be the most helpful.

Current team is Sig(L) Vero, Shannon, Bella, Bernard all 6 except Shannon, with 5-6 star runes.