Kill Me I'll Take the Throne

Right after transmigrating to become the First Prince of Aldoria, who has guarded the border for five years, Arthur Sterling receives an Imperial Decree ordering his execution. What? I command 600,000 troops, and you want me dead? Arthur fights his way back to The Capital, slays the traitors, and seizes the throne. It is only at the very last moment he discovers that all of this was merely a test orchestrated by Emperor Richard Sterling.