Per wiki policy, Spoilers Off applies here and all spoilers are unmarked. You Have Been Warned.
Who would expect, a game with bugs for characters and an overall gloomy atmospheric in hand-drawn graphics can still tug heartstrings with some bits of its lore.
- Later in the game, if you try to backtrack and find a hidden segment above the area where you've defeated the False Knight, you can find two other maggots holding a funeral for that maggot in the armor which you have killed before. Sure, it's touching to see some creatures lament over the loss of a kin, but you have to kill them too if you want to complete the Hunter's Journal.
- If you refuse to kill the Nailsmith, you can find him happily making sculptures alongside Nailmaster Sheo with a new purpose in life. The kicker? The achievement you get from this is called "Happy Couple." Aw.
- The Last Stag, for most of the game, thinks he's Last of His Kind. However, if you unlock all of the stag stations, he suddenly finds the Stag Caves where all the other stag beetles were bred. He takes you to it, and at the end of the area you find a hatched egg. A recently hatched egg. He's not the last one after all, and he recognizes this and changes his name to simply the "Old Stag".
- Myla is a miner bug that is only innocently singing as she mines for pink crystals. However, over the course of the game, she slowly gets infected and turns into another one of the miner enemies that you encounter all over the Crystal Peak. Killing her is a massive Tearjerker & Player Punch moment, however, you can always opt to... not do it. You don't have to kill her after she's infected & hostile. Adding on top of this, defeating The Radiance frees all infected bugs from her mind control, implying that if you let Myla live after she's zombified, she gets returned to normal.
- The Elderbug starts out as a depressed NPC left alone in Dirtmouth, but still waiting for any residents to return. Once the various key NPCs do return to the town, speaking to the Elderbug after the arrival of each one has him express happiness that the town is getting livelier each time.
- Giving the Delicate Flower to Elderbug. He seems to be really touched and grateful for such a gift, even saying that the world seems a little less faded for him because of this unexpected act of kindness. And if you hit him with the Dream Nail after this, you'll get this line.Elderbug: Perhaps dreams aren't such bad things after all...
- Finding Marissa's ghost in the City of Tears, allowing her to perform to an audience once again.
- Crosses over into Tearjerker a bit, but helping the Grey Mourner with her final request. Even though she dies immediately afterwards, letting her find closure after the death of her lover, and hearing how grateful she is for the opportunity to do so, allows her to experience a little more kindness before she gives up on life.
- Sitting with Quirrel after he helps you on your journey for the last time. Despite his memory loss, Quirrel is still grateful that he got to experience Hallownest's wonder all over again, and considers The Knight the most wondrous piece of it all. When he's done talking, simply sitting with him, overlooking the tranquility of Blue Lake, feels extraordinarily rewarding after all the two of you have been through.
- After defeating the White Defender five times, the Dung Defender will awaken in his room, offer The Knight shelter, and suggest that The Knight wouldn't be out of place in the ranks of Hallownest's exalted heroes. After you leave and return, you find that the Dung Defender is gone, and he's made a statue of The Knight, to rest among those of the Five Great Knights the Defender has also created. The Dung Defender can finally be part of a brotherhood again.
- Around the same time that its possible to learn that Hornet is the Knights sister, or something close it anyway, Godhome also becomes available. In it, the player can find and face Winged Nosk, a version of Nosk resembling Hornet. The Heartwarming part comes in remembering that Nosk searches the memories of its victims and mimics the forms of those most important to them.
- Brumm. He dearly cares for the Troupe, and his desire to see their Ritual stopped in Hallownest is born out of concern that it has gone on too long and holds Grimm imprisoned as well. He asks the Knight to stop Grimm, just this once, not out of a desire to get back at Grimm, but out of a genuine belief that his Master will be better off for the Ritual not taking place this once, or even possibly ever again. While he does not hold the Knight any ill will if they go through with the Ritual, his Dream Nail dialogue when he's destroying the Nightmare Lantern and banishing Grimm says it all.Brumm: Master... are even you a slave? If so, let our chains be broken together!
- After banishing the Grimm Troupe, a bug named Nymm appears in Dirtmouth with an accordion who plays Dirtmouth's town theme. He gives the Knight a gift, a charm that marks the beginning of their friendship. The charm looks like Brumm's mask, Nymm has the same clothing and accordion, and doesn't remember how they arrived in Hallownest. It's extremely likely that Nymm is Brumm, finally freed from the Grimm Troupe's cycle. Perhaps Nymm was the bug he was before he was Brumm, or maybe Nymm is a new identity he has assumed after losing his old one. In any event, Brumm, likely now Nymm, is finally free.Nymm: My dear friend, are you enjoying my music? It's as upbeat a tune as I know, but I must admit, even it falls a little on the sadder side. Please know I play it with joy. Being in this town, beside such good company as yourself, I feel remarkably, refreshingly content.
- While the Pale King's efforts to seal the infection are dubious, if ultimately for the good of his people, in spite of all the sacrifices done, there are hints of the king's regret and inner struggles behind the godly image. Even in the Temple of the Black Egg, where the Hollow Knight has been chained up and bound by the Dreamers, the Lore Tablet left behind isn't entirely without a measure of kindness.Vessel. Though bound, you shall know the state of the world.Hallownest will be whole again.
- It's also telling that in the center of the City of Tears, right alongside the splendor of the nobles' quarters and the glory of the capital, in plain view is the memorial to the Hollow Knight, where the memory of its sacrifice is publicly made for all to see.