What your HUmar NEEDS for those twin swords is a /BATTLE unit.
Now, the GOD/BATTLE is only available from Redria and an Ultimate Hilde (as was stated) but the DEVIL/BATTLE will DEFINITELY help. My HUnewearl (Kodachi) set her own twin swords aside for a while because they were too slow... until I gave her a DEVIL/BATTLE, that is! Man, I wonder how fast she'd be with a GOD/BATTLE...
Anyway, you can find the drop rates and where for the DEVIL/BATTLE here:
The main website is:
just in case you didn't know about it. That website roxx! ^___^