"As far as I am concerned, Welf is much more useful than you, and I care about him much more than I do about you, who's only ability is glaring at the back of my head since the day we met. So please, unless its something useful coming out of your oral cavity, keep it closed."
As for how he ended up seducing a princess, gaining a reputation across all nations, and convincing those around him that he is almost the second incarnation of the Avatar, despite only mastering one element, he has no idea. It all happened somehow. Accidentally.
According to Shuna she was a terrible cook at first, but through sheer grit and determination she broke her limits and ascended into propper chef status. It was a grueling and difficult journey, one of the hardest things she has ever accomplished in fact. But she did it, all for her master.
"Dude, you had one job." Minoru sighed, "...I trusted you as a human cupholder since this car only has one, and it's fucking useless. Ah, gosh..." Minoru slapped his face in disappointment, noting that he was a perfectionist who loved his harem—oops, I mean, all his cars.