You need to get the Magus Sisters yourself before Belgemine will use them. For that, you need a couple of Key Items. The Flower Scepter, which you get for defeating Belgemine's Bahamut, and the Blossom Crown, for catching one of every fiend on Mount Gagazet from the Arena guy. Take both of these items, go back to Belgemine, and open the door behind her to get the Magus Sisters.
Ok I'm missing the first and second al bhed primers... second one can bet gotten easily. but how do i get back on that first al bhed ship to get the first primer?
You can't, but if you really want it then go to an earlier save or start over and get it. After that you can compile the primers on your current save file at a save sphere.
There's like, 3 or 4 of them that're missable if I'm remembering correctly.
EDIT: I forgot, if you didn't grab it then it reappears in the Bikanel Desert at an Oasis.
i have aurons celestial weapon fully powered up, but the weird thing is that he only does 1k to 3k damage with it in the omega ruins and inside sin. what i dont get because i went all the way through his grid and are partialy into tiduses grid now.
what gives?
With the Masamune, his physical attacks do more damage when his HP is low and less damage with full HP.