Earlier…
"Saphrilla… I really hope you're okay… You should be in good hands with Xenia, so I'm going to trust her. For now, I'm gonna look for that fucking bitch. I'll apologize to you later," Rein thought to himself as he jumped across the buildings, concealing himself from the citizens as the sun set.
When talking with Saphrilla a little earlier, he felt a familiar pulse of energy spark from the royal palace. He knew it was her, his aunt, along with who he could only assume to be the king of Orthlys, Fredric Orthlysia, Chloe's father. He couldn't feel Luther's energy anywhere, but he could easily be masking it by some unknown means, so Rein didn't put his guard down.