You said that something will happen that made you change favorite characters. I know you have good judgment, so you wouldn't suddenly change them unless some steady development happened during the second half of the series. So it could either be Sheryl being shown in a very good light or Ranka being shown in a very bad light. From the way you worded it your "change side" statement, you said less green instead of more pink, it'd point towards Ranka being shown in a bad light. So yes, it's spoilerful enough.
