Some characters receive far more attention across a franchise than their original role suggested, and the explanation frequently involves what can be manufactured and sold rather than what the story needs.
Licensing is a separate and durable revenue stream
A film earns most of its box office within weeks, while a successful character can generate licensing income for decades through toys, apparel, publishing and countless other categories.
That income is also more predictable, since it depends on an established character rather than on the reception of any individual release.
A studio evaluating a franchise therefore weighs two different things, and a character who performs strongly in the second column acquires an importance the story did not assign.
Some designs simply work as objects
A character reads well as merchandise when the silhouette is recognisable at small scale, the colours are distinctive and the design survives being simplified into a few shapes.
Non-human and heavily costumed characters often satisfy this better than human ones, which is why franchises consistently develop supporting figures of that kind.
Sales data feeds back into development
Licensing partners track which figures sell, and that information reaches the people planning follow-up projects well before any sequel is written.
A minor character selling unexpectedly well becomes a candidate for expansion, sometimes acquiring a backstory and screen time that were never part of the original design.
The reverse happens quietly, where a central character with weak merchandising performance is not removed but is less likely to anchor whatever is built next.
Toy production timelines force early decisions
Manufacturing and distributing a product line takes many months, so designs must be finalised long before a film is complete and sometimes before it is finished shooting.
This is why merchandise occasionally reveals characters or details ahead of a release, and why some products depict versions that differ from the finished film.
The influence has limits
Films built primarily around what can be sold tend to be recognisable as such, and audiences respond poorly to characters that exist for no narrative reason.
The more common outcome is subtler, where merchandising does not create characters but decides which of several plausible directions a franchise takes next.
That is also why franchises aimed at adults behave differently, since a property with limited toy potential is evaluated on other revenue entirely.