Not much is known about this character at the moment.
River seems to be a person with a a lot of patience. Even when others are annoyed or angry with him, he does not boil over. He does care for the group, even though he has not been with them for that long. He also does not believe in carrying a gun for reasons unknown.
Skill Set Edit
River has a incredible abilities with hacking and magic. Both which could and have proven to be very useful. His magic can only be used when he has a Power Fragment in his possession.
In Episode One, he and Kori were in high tension because Kori did not trust him. This tension could have been onesies since River never showed any aggression to Kori. This continued until he teleported the group out of the wasteland that they were in. After that, the two seemed to have made up. It is unclear about how River feels about Brook and vise versa, since they only spent a little bit of time together on screen. He does have what he claims is an other half that he is competing against for Power Fragments, so it might be the case that he does not like him that much.