This a drabble I wanted to get down because I got Sunday on the brain and I miss him dearly. I haven't played in so long so forgive me if this is like, out of date to the new world.
Thinking about Winged Halovian Nameless! Reader with Sunday. Obviously, winged Halovians are rare, and with reader always traveling on the express, they never learned how to care for their wings and feathers until Sunday joined the crew. I can imagine the reader having even tucked them beneath their hair for so many years to hide them because of the attention (and accusations of copying a certain idol wherever they go) causing them to kind of just... Forget they have them.
At first he doesn't really say or do much with you, he's just trying to be as helpful as he can to The Express with his newfound freedom. He's in shock one day when your wings are in particular pain that day and you left them rest on your shoulders instead of being tucked away.
Sunday is horrified at the lack of care towards them. Sure tucking them away is fine for short periods of the times but never having properly preened your own feathers properly plus the constant oils from your hair (that sometimes went days or weeks without proper washing due to being on a planet that didn't have that luxury) made your feathers brittle and some even painfully ingrown.
"so um.... Do you- what do you use to wash your wings?" He would ask tentatively, trying to not immediately offend the reader in his first proper conversation with you since joining.
"shampoo and conditioner??" He's stunned.
"let's maybe.... Not do that."
That night begins the first night of a long drawn routine that he puts himself through every night and now drags you to do the same. He preens your feathers, rubs all the essential oils needed to keep the skin healthy, soothes the ingrown spurs, and gives you the general daily care they'd need. Once your wings are no longer as damaged, he's likely to bring it down to the typical once every one to two weeks. But the self care nights never really cease even when you're plenty knowledgeable and capable of doing this yourself. It's hard when he's just so good making the process so calming and relaxing.
Sunday who helps winged halovian reader become more comfortable with keeping their wings exposed rather than tucking them away into their hair. Practically raising his chin in pride when people comment on how beautiful they look.