# Do you think that I could not call ... angels?

"Surely you know that I could call ... angels." 

# Do you think

Here "you" is singular and refers to the person with the sword.

# my Father

This refers to God the Father. It is best to translate “Father” with the same word that your language uses to refer to a human father. 

# more than twelve legions of angels

"more than 12 really large groups of angels"