I'd like to fucking mention, LiSA and Horikoshi, author composer signer of the Fantasy Ending of S2, and author of the manga, says that the song is about Midoriya's true feelings about Kacchan.
*cough cough* lemme just... tell you one or two lines about it.
The song is "After All, You're my Hero!/ Datte Atashi no Hero!"
*sharp inhale*
YOURE BOLD
AND ALWAYS SO COURAGEOUS
I CAN NEVER SEE YOU QUIT
*SKIP*
WE ONLY HAVE ONE LIFE BUT WHEN WE ARE TOGETHER WE CAN WIN
*skip
SHOUTING OUT, IM CHEERING LOUDER CAUSE YOU MAKE ME FEEL THIS WAY
*skip
WHEN I LOOSE MYSELF IN YOUR EYES
I FEEL BETTER- I CANT UNDERSTAND THIS PART
*skip
NO MATTER IF THE OTHERS CALL YOU NOTHING MORE THAN A CRAZY FOOL
I GUESS IM FOOLISH TOO,
BUT I WONT LEAVE YOUR SIDE
CAUSE TOGETHER WE CAN BREAK THE RULES
*skip
SHOUTING OUT, YOUR CHEER GROWS LOUDER,
I CANT HELP BUT TRULY SMILE
*skip
AFTER ALL YOURE MY TRUE HEROOOOOO!
*end*
IM FUKIN SORRY BUT DEKU SINGS THIS TO KACCHAN *LOUD COUGHS* "CAUSE YOU MAKE ME FEEL THIS WAY" HAHAHAHHAHAHA DONT TELL ME THATS NOT A CRUSH MAN HORIKOSHI SECRETLY SHIPS KATSUDEKU WE HAVE AN ALIBI ON OUR SIDE TODODEKU GOT THE TOURNAMENT ARC WE HAVE THE BEHIND THE SCENES AND JUST A BIT AFTER THE KAMINO INCIDENT ARC (I FINISHED THE MANGA (THE 187 CHAPTERS PUBLISHED SO FAR) AND THE KATSUDEKU PRESEMT IS BEAUTIFUL BUT AFTET THAT DEKU GETS A BIT ISOLATEX AND ONLY REALLY HANGS OUT WITH TOOGATA, AOYAMA, ASHIDOU, JIROU AND ERI CAUSE OF THE SHOW GOING ON)