Charon/Plot

Background
Charon was presumably made to keep tabs on Giev they were also shown talking to someone else(presumably Lamia).

Additionally Charon has the ability to erase memories or at the very least Giev's memory.

Fugitive Arc
Similar to Giev, Charon first appears alongside him who were watching Jin and Tachikawa (with Izumi in the background) destroying Arugdas with only one strike for each trion soldier as commented by Giev. In response to his comment Charon complimented the duo and asked Giev if they were the trigger users from meeden Ergates was talking about beforehand then followed up with how they might get in the way of their mission to which Giev responded with how they won't be a problem if that's all they got.