The twins didn't need to look around to feel the presence of quite a few powerful Divine Senses. Those experts weren't hiding themselves, so the twins could see from which powers they belonged. There were experts from the Realm of Gods, Heavens, Underworld, and even some Vruves.
Those experts weren't there to take part in the exploration, though. Instead, they were there to protect the tunnel. You never know if someone will try underhanded methods, so they were all carefully paying attention to the entrance and the surroundings, ready to attack anyone who tried anything against the entrance.
Rean didn't stay there for long, turning around and preparing to leave. 'Alright, let's take this opportunity and go to the Hustis Continent. We have a Fragment to find there anyway. Forget about this Hidden Realm and the Quest. It is not worth it.'