The Mysterious woman has brought Ecarlate and her group along with Erec and his team to tell them the reason behind everything.
I thought the mission was 
carried out by two units.
Pensaba que la misión había sido 
llevada a cabo por dos unidades.
Pensaba que la misión había sido llevada a cabo solo por dos unidades.
Eu pensei que a missão seria
 realizada por duas unidades.