If Hideyoshi and Mitsuhide are on opposing sides during a banner battle (like in Viperia), the two have a special exchange of dialogue:
Hideyoshi: "We can't lose to Mitsuhide! We've got to get those banners first,(Pokemon)!"
Mitsuhide: "We shall not be defeated. Come, (Pokemon)."
This is likely a reference to the Battle of Yamazaki, in which the real life Akechi Mitsuhide and Toyotomi Hideyoshi fought against each other, after Mitsuhide had betrayed and murdered Oda Nobunaga.