Reasons

Every resident of the Fallen Fate knew of Fate as a great entity, as well as Chaos. However, only a few knew that Fate was as capable of evil as Chaos was of random good. One of the rarest knowledge was the existence of the Shattered Moon Order. 

Erel and Solomon knew of their existence, Anet too, as an experienced Oracle, she knew many secrets that others had no idea about.

Rea was the only one who hadn't known about the existence of such an organization until now, so she was curious to hear more about it.

Erel took a deep breath and said, "Rea, the Shattered Moon Order has not taken one clear stance. They are not allied with the Fate or Chaos. They act at their own discretion, and do as they see fit."

"Hmm...? Doesn't that make them just a neutral organization?" Rea tilted her head in confusion, "Why would Order want to destroy them in that case?"