Here's a story idea that I've had in the past. It came to me again:
Keigo is a Heteromorph and was born with wings, red feathers in his hair, downy feathers covering his neck, feathers covering his torso, feathers around his wrists and ankles, scaled Bird hands and feet tipped with deadly sharp talons, deadly sharp fangs, four short tail feathers that end at his knees, Tomia covering his tongue, the inside of his cheeks, and going down the inside of his throat. (The Commission took the extra features away. The League gave them back.)
Keigo is twenty-three. Touya is twenty-seven. Keigo is a whole head shorter than Touya thanks to his Bird Quirk. Keigo has heightened senses and can sense and hear for LITERALLY three miles.
*After the war. The League members (Kurogiri Atsuhiro Magne Jin Touya Tomura Shuichi and Himiko) are all dead. Keigo didn't betray them.*
A girl about fifteen-years-old has a Quirk that lets her look into the minds of people. She then sings a song that represents that person's emotional and mental health, hypnotizing that person with her singing at the same time.
She is on a stage, singing to a group of people on the stage.
A crowd of civilians and Heroes have gathered. One, because the girl is using her Quirk illegally. And two, because Keigo is one of the people on the stage.
When the girl gets to the Bird, the crowd expects a song about triumph about winning the war.
Instead the girl starts singing a song about depression and wanting lost loved ones back.
Unknown to any of the living people, the League members are ghosts (Kurogiri has his full Oboro memories back) and haunting Keigo. Not out of rage, but out of love and protection.
The ghosts aren't happy that the girl is revealing their Bird's emotional and mental issues to everyone.
Suddenly, the girl starts glowing as she continues singing, to the confusion of the crowd. This isn't in her Quirk registration file.
See, the girl has a secret second Quirk that her parents kept secret to protect her. She can send someone back in time, putting them inside their past bodies.
She's decided Keigo is at risk of becoming Suicidal and has decided to fix it. She knows, from seeing his memories, that he'll absolutely help the League and make it so they win instead. She doesn't care. She's a fan of Keigo. Not Heroes or Villains.
The ghost League feels what the living doesn't. Time is starting to slowly rewind.
"I've changed my mind, I love this kid," Tomura grins.