>>93179510my prediction:
Toffee is connected to Eclipsa, somehow, and intends to use her as a key part of his plans. Showing them together in Into the Wand implies an established past relationship rather than just them interacting in the future-- wand is linked to memories after all.
Eclipsa may not go along with it though, either because of her mindset changing since she saw him last or backing out after seeing how much Toffee has changed over the years. She'll end up working with Star instead as her new post-Glossaryck mentor figure, possibly using her knowledge of Toffee to help Star out.
Eclipsa is misunderstood to some extent despite her dark magic, and mostly just wants to fuck monsters and not get involved with Mewnian shit anymore. She may see the current Butterfly dynasty as something she doesn't want to support/save, but not actively work against it herself the way Toffee is. For this reason she may be initially unwilling to help Star as well, and possibly would only do so after realizing Toffee is causing even more damage through his own plans.
