Asymptotic Giant Branch (AGB) / Red Giant Branch (RGB)
Not explicitly provided; however, a relevant analogy is "Wisty's interactions with Sunny were more predictable than when it was on the other branch." This can be related to the crianca summary's "when you clean your room and there are a lot of toys everywhere" - both situations imply a change in state or transition between distinct phases.
Technical definition
AGB: a stage in the evolution of low-to-intermediate mass stars where they expand and cool, forming a shell around themselves before undergoing thermal pulses; RGB: an earlier phase in which stars are on their way to becoming red giants by fusing helium into heavier elements