MX meeting every single Luigi in Mario's madness is such a fun and cool idea.
He must be very confused since he is trying to find Lucas

I imagine that the final scene is MX ignoring all of Mr. L's copies and dashing straight for his real soul. Killing ghosts might've been Luigi's specialty, but MX is more than capable of getting the job done.

these two are really interesting creatures. MX is an ancient spirit possessing a Mario game, taking the appearance of Mario trying to lure victims (such as Lucas). He tries to chase his victims and kill them brutally, bur Mr L is different. He's actually Luigi, which makes it seemingly scarier. after he was killed by Mario by mistake he came back and instead of just straight up trying to kill him like MX would, he attacked Mario mentally after killing and reviving Mario. then made Mario suffer the same fate as Luigi. and what makes it worse is Mr L. didn't let Mario's spirit go. he kept it as his slave for the rest of eternity. these two stories are both messed up, but when they meet each other, it'd be like an immovable object vs a unstoppable object.

“LUCAS, THERE YOU ARE! HIDING IN A FOREST DOESN’T GET-“

“Yo soy Luigi. Mama Mia. Luigi.exe soy amigo de la Mario madness.”

“WHAT THE FUCK ARE YOU ON ABOUT, LUCAS?!”

2:22 WHY DO MX AND THE FORGIVEN SOUND SO GOOD SINGING TOGETHER

Mr L: “Dang, so we both screwed up.”

MX: “LUCAS WHAT ARE YOU TALKING ABOUT?!”

Mr L: “WHO???”

- After the song -
MX: ok, that wasn't lucas either

Tall lucas: yo soy luigi mama m-
Big mario: TALL LUCAS!!!!
tall lucas: IM NOT LUCAS!!!

Ghost Mario and MX almost have the same move set. I literally just noticed it

2 brothers having a laugh: 0:23

After MX's failed attempts to find Lucas, it seems that he found the real Lucas.

MX: Luca-
MR.L: I will show you how much suffering i get from this F##KING meme!!!!

Mr L: how the heck are you still alive brother?
MX: I finally found you Lucas!
Mr L: who is Lucas?
MX: YOU ARE LUCAS!
fight starts
MX: TALL AHH MF
Mr L: hypocrite
OGN Luigi: like can you actually just kill yoursel-
MX rips OGN in half while Mr L just watches confused

2:16 Mx: oh hi the other me

Lore of it (in my opinion):
MX came by another Luigi, but thinking it was Lucas, he started to sing with him. After seeing it wasn't, he heard that Mr L knew of Lucas' whereabouts somehow and during it all, MX learned to know where Lucas might be
(Just my thoughts on what it would be)

You can tell he put a lot of effort into it with all those extra notes.

2:32 MX and The Forgothen with the same sprite

0:22 MX: look, i know what a disguise looks like... youa re not lucas. lets just drop the acts and spit bars
2:21 Mr.L: lookie here, decided to show up, dear brother?
MX: WHO TF ARE YOU?!

YO SOY LUCAS, MAMMA MIA. LUCAS EL NIÑO QUE QUEDO ATRAPADO EN EL MARIO'85

Mr L : AH HAHAHA!
MX : chokes on his saliva