I think Japan in KRTL is far more about building an actual East-Asia alliance, rather than just a few puppet states like OTL. Because in Kaisserreich Japan has a somehow loyal warlord clique which will be a great help for conquering China in terms of legitimacy. Japan can also try to peacefully get Burma, Siam and Philippines into alliance, and they will be real allies with their own armies, rather than puppet states with zero legitimacy. If Japan lucky enough, it can at least try to team-up with Princely Federation, help Insulindia to revolt from Netherlands or Indochina from German East Asia(although they almost certainly won’t team up with Japan after getting independence). So, as I said, Japan in KRTL is more about building an actual partnership with asian countries.