One creative plot could be that the Knight from Hollow Knight ends up in the Underground of Undertale. The Knight's silent and determined nature could create interesting interactions with the talkative and emotional characters in Undertale. For example, when meeting Sans, the Knight's combat skills might be put to the test in a friendly spar with Sans' unique attack patterns. Another plot could involve the characters from Undertale finding their way into Hallownest. Frisk's pacifist nature might contrast with the often hostile environment of Hallownest, and they could try to find non - violent solutions to the problems there, like befriending the bugs instead of fighting them.
If we consider the healing abilities in both games, the bugs in Hollow Knight that can heal the Knight could teach Toriel about new ways of healing. Toriel could then use her magic in combination with these new techniques. The Knight's ability to climb walls and ceilings could be combined with Napstablook's ability to float. They could create a new form of movement that allows them to access areas that were previously unreachable. And the magic attacks of the Undertale characters, like Muffet's spider webs, could be enhanced by the magic of Hallownest, making them more durable and effective in combat.
Some characters might be amused. For example, Sans would probably make some witty remarks about the fanfiction's plot twists. Papyrus, on the other hand, might be a bit confused at first but then get really excited if he finds a heroic role for himself in the fanfiction.
In the Hollow Knight story, which is centered around the desolate and mysterious world of Hallownest, there are no obvious references to a 'familiar zero'. The game focuses on themes of sacrifice, decay, and the struggle between light and dark. There are bugs with different abilities and backstories, but this 'familiar zero' seems not to be part of the main narrative as far as I know.
Hollow Knight definitely has a story. It's a deep and immersive one that keeps you hooked. You'll discover secrets, encounter unique characters, and piece together the narrative as you explore the game's vast and beautiful world.
The story behind Hollow Knight is centered around exploration and discovery. You'll encounter strange creatures, forgotten lore, and a web of interwoven narratives as you delve deeper into the game's immersive world.