I would just like to make a quick point, if RKT was able to blast the so called 'Gods of Gods' into oblivion then Im sure he could at least face off against Galactus? I'm not saying RKT would beat him, but would at least give him a pretty good fight.
The Rune Power seems to have unknown limits, this is shown by how Thor was much more powerful than his father, Odin, ever was but they never showed the true extent and limits of this power. End of the day, it's anybodies guess, but seeing how Thor broke the cycle of Ragnarok which not even the all-father could do shows maybe a glimpse of this power. Hopefully Thor will one day touch upon this power in a time of need, and soon.
dude they need to make another comic with that already, how powerful were the runes? The guys talking to thor about joining them or something.
The guys asking about Thor joining them was 'Those Who Sit Above in Shadows', not the Runes. But, for me at least, it's hard to say exactly how powerful the Runes were.