He hadn't seen one of his siblings in months - not since back home, when Hester and Inias had come for Kevin - but there was another angel here. Castiel was certain of that. Well... almost certain. There was something off about the presence that he sensed, something different. He left Dean rather abruptly to fly off in search of this presence, but he would explain later. Right now, he needed to find out if it was true, if one of his brothers or sisters had come here.
Castiel landed beside the bench with a audible flutter of wings. His wings were invisible to the humans passing by, but if this was truly another angel, then he should be able to perceive Castiel's true shape, squeezed into his human vessel. Although... now that he was in front of this other being, Cas wasn't so sure. The other being occupied no vessel, yet he'd shifted his form into something more like a human visage. This was not one of Castiel's brothers or sisters, not exactly, though there was such a similar feeling coming from him, surely he couldn't be far off. It was close enough that Cas could set aside the other feeling of something like Hell that also seemed to cling to him - that could wait.
"Hi," he said after taking a moment to just stare, unabashed. His voice was rough, but gentle, his face alight with his curiosity. "I could sense you from the other end of Preya. Are you... an angel?"