Minato is a very smug and arrogant person this was shown when he addressed Sekai as a looser after he saw Sekai win a Gunpla Battle. He is also very smug and thinks he is the best builder in the world.
Minato showed up presenting a Master Grade NZ-000 Queen Mansa sadly he found out that Yuuma Kousaka had won the competition and this annoyed Minato so he left in a bad mood. He Later met Hoshino and Sekai in a shop where he rudely called Sekai a Looser for no reason and claimed he knew nothing he then challenged him to a Gunpla Battle Hoshino pointed out he had no Gunpla and he replied he can build one in an instant so he picked up a Kouki Gundam SD and tossed the content into the air then pulled out his Clippers and built the SD in a matter of Seconds. During the fight he kept insulting Sekai and telling him he is a weak fighter who doesn't understand Gunpla Battle Sekai then unlocked his Musha Godmaru's hidden Power Sadly Minato then revealed his Gunpla could transform he then won the fight and then left after giving Sekai one last insult.