(Sounds like the Doryu Ghost Squad from Rave.)
I have a theory on the Nine Demon Gate.
What if they are similar to Dante's Inferno's Nine Circles of Hell?
These are some of my theories if they are reflected by the nine circles of hell.
1. Tempesta: Limbo
2. Sayla: Lust
3. Torafusa: Gluttony
4. Franmalth: Greed
5. Ezel: Anger
6. Keith: Heresy
7. Jackal: Violence
8. Kyouka: Fraud
9. Silver: Treachery
EDIT: All the members revealed.
What do you guys think?