Swin

A young girl whom Shannon finds outside a town. She claims to have no parents, and said she was waiting for somebody, though she did not know who it was. She follows Shannon home. After a few strange occurrences involving her, Zefiris informs Pacifica that Suin is a Peacemaker in a compressed state (the human girl form) and, on top of that, an artillery type that can cancel out the Dragoons' presence. As if to prove this, as soon as Zefiris says that, Pacifica sees Zefiris disappearing, just as Suin walks into the room. Suin was compressed because artillery types were powerful and dangerous, so to keep them in a more stable condition, Cz was compressed as Suin.

Galil, it turns out, was supposed to pick Suin up at the bridge and release her true form, but was eliminated by Zefiris before he could. Steyr went in his place to seek Suin out, finding her with Pacifica and finally "unzipping" her compressed form, causing her to revert back to Cz, the Peacemaker. There was in fact, some foreshadowing about Swin's true identity. In episode 8, when Shannon said that she might be killed if she stayed with them, she replied "I don't die." (which is in in fact true as Peacemakers are immortal). Also, she mentioned that she had no parents when Raquel inquired about it, not that they did or she got lost, but that she simply didn't have parents.

In addition, when Pacifica tried to catch up with her in the woods, Pacifica was nearly out of breath while she was not even panting. (Source: Wikipedia)