Tiel casually mentioned a few words, but they stirred waves in Gawain's heart, because he recognized the vast amount of information within that short exchange!
The sea demon is an ancient and mysterious civilization, a deep-sea race that has lived beyond his "Satellite Surveillance Area" and was already quite advanced tens of thousands, if not hundreds of thousands, of years ago. Although the race's technological development seems to have stalled and hit a bottleneck due to the chaotic wave, they have at least persisted through the ages—and in the process, left extensive observation records of land civilizations.
Compared to Gawain's later "waiting a thousand years for a frame" situation, the sea demons' observations are evidently more continuous, detailed, and reliable.
Thus, Tiel's words should be trustworthy.
