If you ask if there are any usable characters among the regular ones, excluding the 'bean pods'...

I would choose Madison Melancholy. This is because once an enemy is caught in a poison spell, you can destroy all their barriers with Last Word, even if you lack boost. It will be particularly useful in Main Story Chapter 2. What about Aiki, who I use often? Be careful, she's a bit off before her reincarnation. Annoyingly, her spirit recovery skills only recover 0.8, so if you don't reincarnate, you won't get 3 boost from the start.