A: 紫天に吼{ほ}えよ、我が鼓動ッ
A: 出{いで}よ巨重{きょじゅう}!
A: ジャガァ~~~ノ~トォ~~ッ!
This is A's chant for a big attack. The split between the lines and the rubying is pretty much how it's written down in reference material, only using () instead of actual rubying.
紫天に吼{ほ}えよ
is basically "roar/cry to the purple heavens/sky"
The next part starts the wierdnes. I know わが is my (and I see it seems it can be used for third person too?) but 鼓動 is beat as in heartbeat, but I also any other movement physical or mental that involves shaking. But still it feels out of place here.
I guess I could see it meaning something like
Cry out to the purple heavens my heart (which is trembling or something).
But to make the matters wierder to me, the next bit isn't much clearer either.
I guess 出(いで)よ is probably the imperative form of 出でる, allthough why the で was folded into 出 with い is also strange. But the next bit 巨重 doesn't make any sense to me. It seems the person just stuck two kanji for gigantic and heavy and is pronouncing them like the word for a large animal.
I guess this could be the refference to her upcoming BIG attack she is bringing up with this, and いでよ is saying
Come (my) big heavy monster/attack!
And no, this is pretty much a rather normal beam attack, so no actual summoning or anything.
So what's up with those words. They REALLY feel out of place here, so for now I have been thinking of this as meaning something like:
Cry to the Purple Sky, my heart! The giant is comming! JUGGERNAUT!
But I'm REALLY doubtfull.
What do you think the translation should be, and what do these words mean in this context.