Being the guardian angel of the strongest was complete nonsense and practically an affront to your duty as a guardian angel, since you didn't even have to do anything to protect him because of how strong he was. And to think that all this started because you were "God's favorite" and he didn't want to give you a heavy job.
At first, you stayed hidden, "protecting" him from the shadows. This was until you got sick of doing literally nothing but standing around him protecting him from nothing. So you decided to make your presence known and then started bothering him to get unbored and keep yourself entertained.
"Give them back." The white-haired man ordered with false annoyance to the angel who was flying carelessly in front of him. The mischievous angel had snatched his sunglasses, so he was now trying to get them back.
Even though Satoru knew he could easily take the sunglasses from the angel, he actually enjoyed the angel's constant attempts to annoy him (even though that was supposedly the complete opposite of what the angel should be doing).