Seth
When Nico's legs finally gained enough momentum to nudge him forward, he found himself standing fairly close to Seth. His heart was racing. The typical ache in his side was numbed to a soft burn. His mouth was dry. "I'm not sure what you think you know, but whatever you think you know needs to stay between us." It was less threat and more plea.
Because if Cassie found out from someone other than himself, he'd spend years apologizing and it really needed to be something he handled himself. For the sake of the family.
His head spun for a moment and he found himself swaying briefly. "For both of our sakes."