I like the Assassin's Blade, the release Mortal Danger looks like Karst's Death Scythe.
The Masamune's Rising Dragon is cool, but only in Lost Age, in Dark Dawn it looked poop.
I like Titan Blade from the Gaia Blade, although the Dark Sword's release, Acheron's Grief is similar, and cool looking.
Megiddo is awesome move, definitely!