I've tried to find an explanation, whether it be theological, historical, or better yet, a variant reading of Isaiah 9:5-6.
angelos megales boules
as it happens the lxx just has a butchered rendering of 9:5-6. the worst part isn't "Angel of great counsel" it's the lack of "everlasting Father". "Angel of great counsel" is acceptable, if weird, as a rendering of the angel of Yahweh. I'm annoyed substantially but this variation. What makes it even more complicated, is that the MT's rendering is clearly the original one. It's rather shocking that the MT is MORE CHRISTOLOGICAL than the LXX. This is bizarre enough for me to think of throwing an tantrum
. I kid. Regardless, is there anything out there? It appears to be counsel, NOT "council". so I could not specifically say this is the angel of Yahweh who heads the divine council with boules.