Down with Velius, Thanks to all, still a few ?s

[Miluda]

If you managed to defeat Wiegraf by Ramza alone, then you shouldn't have a problem with Velius.

Level 40 Ramza is enough. It's very natural for such enemies' levels to be higher than yours.
I would ignore his minions and concentrate on attacking Velius himself. If your Ramza has learnt the 'Yell' ability, it would make the battle easier. All you really need for this is Ramza and someone else who can use Phoenex Down and maybe Agrias or another strong ally to keep the other monsters busy.

EDIT
Sorry, I meant 'Accumulate' ability, not 'Yell'; but 'Yell' is very helpful aswell.