What is the name of a man investigating ancient books and novels?

The protagonist who scattered immortals on another plane was sealed for thousands of years. Later, because of the sectarian crisis, a female supremo of later generations seemed to know the existence of the protagonist classically, and then went to let him go with the elders because she believed it. He crossed the universe without hesitation and came to this planet where magical civilization prevailed. Clash between fix true civilization and magic civilization. The peak of the realm of cultivating truth-scattered immortals, the highest achievement of magical civilization-"supernatural" class warships.