Watching his disciple training so hard under his tutelage, Arthur reminisced and reevaluated his goals.
Upon learning the fraction of the future that he saw before he arrived at Argoth Continent, Arthur realized the very reason why his previous self lost the war against those Outer Gods whereas disguised themselves as the Pope of Holy Church.
The cause of his defeat was, at that time, he concentrated all the strength he had on himself. He does not have the support of any party, and he was too arrogant at that.
There was an old saying, "If you can't defeat your enemy, become your enemy."
Therefore, Arthur was willing to do anything to achieve his goal, manipulate everyone at his disposal to do his bidding.
Before he could defeat the Outer Gods, he must build his own army, a kingdom, or even the whole empire and spread his influence and amass more people to join his cause.