Liquid mana.
Kayden felt exactly this sensation with his spiritual sense. The man was so concentrated that it formed a lake in place. He warned his companions and went ahead at high speed. As he got closer, his spiritual sense began to sense some more detailed things. First, there were a few other humans in the pool, but not even a single animal was present. They were just two humans, but Kayden could feel that they were both at the eighth level of the first realm. In other words, they were strong. Kayden couldn't be careless here, but if he needed to, he was confident in giving both of them a hard time.
"Hello," Kayden's voice caught them both by surprise and caused them to assume aggressive fighting stances. Kayden did not exude even an iota of mana from his body when he concentrated, which made him almost as if he were an inanimate object to the other spiritual senses.
"Who are you?"