At least, a "modern day" Knight. And I don't mean "warrior who obeys royalty", I mean the romanticized versions, who exemplify chivalry, loyalty, and kindness. He "slays dragons", sometimes literally (Bowser is a Fire Breathing Lizard, after all!) , in order to help those who need it without asking for anything in return.

He's a great hero known throughout the land, with noble deeds that will go down in legend.

He wields a hammer instead of a sword, overalls instead of armor, but he's ever bit a knight as Lancelot or Galahad of legend.

oh absolutely, full agree

Which, in turn, also makes Luigi a knight since he has those same traits - and doing them while being terrified, which ups the heroism! Plus, brotherhood is another Essential Trait of being a knight, and anyone who knows the Mario bros knows how strong their bond is. So, not quite enough members for a round table, but a Brotherhood of Knights to be sure.

Luigi as he is would fit right in with the other weirdos at the Round Table

if Sir Melion qualified, then Mario and Luigi do

Yoshi also definitely counts as a Noble Steed, given that he can be as kind and heroic as his "master".

Exactly!

I've always had a soft spot for the Mario Bros (even rped as Peach back in Livejournal days!)

And continuing on, Peach is less a damsel in distress and moreso a Regal Princess, who faces each trouble with dignity and has complete faith the Knights. Always carrying herself with grace and tries to help all in her kingdom and beyond.

She always does her best to keep her emotions in check, because she is a princess - her people need her, so she has to represent her people in a dignified matter.

Peach is an icon! It is good that over time, Nintendo's been increasingly removing her from the damsel-in-distress role

Hell yeah. And I'm so glad her latest solo game was so good. I hope it allows them to do more with her.

Yesss. There's a good chance it can lead to more good things for her!