Q: If Sebastian kissed Grell and William caught Sebby kissing him... what do you think... what would Will do to Sebby?
A: Well, that depends on when it happened, the atmosphere, every ones feelings, and the reasoning behind the demons' actions;
Situation 1:
Setting-Right after the killing of Madam Red and the big kick to Grell's face.
Cause-Sebastian kisses Grell and shocks everyone, he then takes the chance to plunge the chainsaw through the abdomen and effectively kill Grell.
Effect-William then at first goes to help the redhead but in return gets injured by the demon with a kick. William would fight back, angry and sad. Then Ciel would call Sebastian off saying that there's no need to waste time with another shinigami. William will keep trying to attack the butler, but will have his scythe broken in order for the fight to stop.
End Result- William maybe shedding a tear over Grell's lifeless body.
Situation 2:
Setting-In the library as the angel is holding Ciel
Cause-Sebastian kisses Grell to get him to try and kill, or at least injure the angel.
Effect-Grell does exactly what Sebastian says, leaving William to forget about ever being with the redhead because of his willingness to do such things for such creatures.
End Result-William forever rejecting Grell
Those are the only two situations I can think of, sorry :P
