I draw this inspired by official T-shirts design for Super Mario Run launch event. Show this tweet
It's seem Mario is dressed as Yukimura Sanada is historical general in Japan.
Then, I thought Bowser should be dressed as Ieyasu Tokugawa is Yukimura's rival.
In the history, General Ieyasu had won the decisive battle.
I hope that Bowser will defeat Mario too in the next, Super Mario Odyssey!!