Luigi, Mario's younger twin, has always been the brunt of Nintendo's little jokes. He's portrayed as being cowardly and is constantly in Mario's shadow, but he certainly tries his damnedest and is worth his weight in gold. As such, he'll be the star of this article and I'll be going over every little detail I can think of about his personality, the way he dresses and even why he idolizes the one who constantly overshadows him. So in the words of Toad, here we go!
Luigi started idolizing his brother at a very young age when in Yoshi's Island, the infant Mario and his temporary guardian Yoshi saved him from the clutches of the evil Kamek, Baby Bowser's caretaker. This drove the young Luigi to follow his brother everywhere he went, even going as far as dressing like him but in a color that compliments red. He even pushed himself to be the best he could so he could help Mario with his quests as evidenced by the fact that Luigi can jump higher and run faster than Mario, but Luigi isn't without his flaws.
Luigi is an odd case. Unlike his twin brother Mario, who is brave and heroic, Luigi is a bit of a coward. If the journey to save Princess Peach proves to be too harrowing for Luigi to handle, he will likely stay in the Mushroom Kingdom and take care of the cleaning and general upkeep of their house. But this isn't always the case. In Paper Mario: The Thousand Year Door, Luigi has been shown to actually help others when they need it and even go on quests of his own if Mario is unavailable. This proves that Luigi has an adventurous side that doesn't always show. But no matter how much or how little Luigi goes on adventures, this does not diminish his fear of ghosts.
Luigi has been in a few scenarios in which his fear of ghosts is evident, but none are more prevalent than in the Luigi's Mansion series. In those games, Mario is the one that needs rescued and Luigi is the only one able to get the job done, and because it was the Boos that abducted Mario, Luigi is at quite the disadvantage. As I said before, Luigi is very much a coward, especially when it comes to ghosts, but when his brother needs help, he swallows his fear and tackles the problem head on. Because of Luigi's timidity, he is easily startled and is often unnerved when placed in stressful situations. As such, he hums and whistles to himself to cope with being in such an unsettling environment. However, he has been shown to overcome this fear as at the end of Luigi's Mansion: Dark Moon, he adopts the ghostly Polterpup that had been teasing him throughout the story.
Now because of the fame and notoriety that Mario gets compared to our titular subject known as Luigi, it is not hard to imagine that under all of that idolizing that there may be a bit of resentment, especially considering that Luigi's name is often forgotten by the citizens of the Mushroom Kingdom and even by Bowser, King of the Koopas. This is actually evident in Super Paper Mario as his mild resentment toward Mario allowed seeds of darkness to be planted in his heart by Dimentio. This is probably Luigi's greatest weakness as while he has braved the forces of many ghosts, he can't seem to come to terms with the envy that he has for his brother's life.
Luigi isn't in any way perfect. He's a coward, he resents the brother he looks up to, and he is often the subject of ridicule. But I like Luigi all the more for it. Adversity builds character, and if The Year of Luigi is evidence enough, he may someday become even more popular than the brother he holds in such high regard. But until then, I'll be seeing you.