Hollow Knight and Silksong

Hollow Knight

At the outset, the player-controlled insectoid warrior arrives at Dirtmouth, a quiet town that sits just above the remains of the kingdom of Hallownest. As the protagonist ventures through the ruins, they learn that Hallownest was once a kingdom of insects which fell after becoming overrun with "The Infection", a supernatural disease that can control the minds of bugs, driving them to madness and undeath. Hallownest's ruler, The Pale King, had previously attempted to lock away the Infection in the Temple of the Black Egg. Despite the temple's magical seals, the disease managed to escape, and Hallownest fell into ruin. The protagonist's mission is to find and kill three bugs called the Dreamers, who act as the living seals on the temple door. Once the seals have been removed, the protagonist may confront the source of the Infection. The protagonist frequently encounters Hornet, the daughter of the Pale King, who tests the protagonist's combat prowess in battle.
Through dialogue with non-player characters, environmental imagery, and writings scattered throughout Hallownest, the protagonist learns the origins of the Infection. In ancient times, a tribe of moths that lived in Hallownest worshipped the Radiance, a primordial being who could control the minds of other bugs. When the Pale King arrived at Hallownest from afar, he used his powers to give sapience and knowledge to the creatures of the realm. The moths joined the bugs of Hallownest in worshipping the king, causing the Radiance to fall into obscurity. Beneath the notice of the Pale King, some worship of the Radiance continued, allowing her to remain alive inside the Dream Realm.
Hallownest prospered until the Radiance began appearing in the dreams of its people, poisoning their minds with the Infection. In an attempt to contain the Infection, the Pale King used a living substance called Void to create the Vessels, creatures made to contain the Infection within their own bodies. The Pale King chose a Vessel called the Hollow Knight, to trap the Radiance within itself, leaving the others locked in a pit called the Abyss. After the Hollow Knight was locked within the Temple of the Black Egg, the Radiance persisted within the Vessel, weakening the temple's seals and allowing the Infection to escape.
Throughout the game, it is revealed that the protagonist was a Vessel who managed to escape the Abyss. They gradually defeat the Dreamers and their guardians, removing the seals on the door. Inside, they encounter and battle with the infected Hollow Knight. Depending on the player's actions throughout the game, multiple endings can be achieved. These include the protagonist defeating the Hollow Knight and taking its place containing the Infection, another where they defeat the Hollow Knight with Hornet's assistance, and the third ending where the Knight uses the Void Heart charm to control the Void, allowing them to attack and defeat the Radiance inside the Dream Realm.

The Grimm Troupe expansion

In the second expansion to Hollow Knight, a "Nightmare Lantern" was added to the Howling Cliffs area. After striking a masked bug with the Dream Nail, the lantern summons a mysterious group of circus performers to Dirtmouth, who identify themselves as the Grimm Troupe. Their leader, Troupe Master Grimm, gives the player a quest to collect magic flames throughout Hallownest in order to take part in a "twisted ritual", feeding off the nightmares of the dying kingdom to keep the Nightmare Heart alive. He gives the player the Grimmchild charm, which creates a small creature reminiscent of the Troupe Master when equipped; when it later absorbs the flames into itself, the ritual is progressed, and the Grimmchild gains the ability to attack the player's enemies. Eventually, the player must choose to either complete the ritual by fighting Grimm in his powerful Nightmare King form or prevent the ritual and banish the Grimm Troupe with the help of Brumm, a traitorous troupe member.

Godmaster expansion

More content was added to Hollow Knight with the fourth and final expansion, Godmaster, in which the player unlocks a new area, Godhome, which includes several boss rushes, and the Hall of Gods, a hallway of statues of the game's bosses, which, upon being selected, allow a rematch. The expansion focuses on the Godseekers, a tribe of bugs from a faraway land, abandoned by their gods. After obtaining the Godtuner, the Knight can help the Godseekers attune to the gods of Hallownest by completing five Pantheons, each containing a set of bosses that must all be defeated consecutively without dying. The final Pantheon, the Pantheon of Hallownest, contains every boss in the game or alternate forms of original bosses. If the player completes the Pantheon of Hallownest, the Absolute Radiance, a more powerful version of the Radiance, appears, acting as the new final boss. Upon defeating her, two unique endings can be achieved in which the player transforms into a powerful Void creature and destroys Godhome.

Hollow Knight: Silksong

Hollow Knight Silksong takes place some time after the events of Hollow Knight. A group of veiled bugs capture Hornet, taking her to the land of Pharloom, a kingdom populated by many pilgrims seeking to reach the Citadel, a religious society located at its peak. Hornet escapes and falls into the depths of Pharloom, deducing that the veiled bugs sought to bring her to the Citadel due to her ability to produce silk, a substance used by the society for various purposes. She journeys to the Citadel to confront the veiled bugs, along the way fighting many creatures afflicted by "the Haunting" an otherworldly force found in Pharloom's silk which reanimates bugs and drives them to madness. Hornet repeatedly encounters Lace, a child-like fencer who taunts her as she approaches her destination.
Through dialogue with non-player characters and environmental imagery, the player is given insight into the history of Pharloom. In the distant past, a godlike "higher being" named Grand Mother Silk became monarch of Pharloom. She used her powers to evolve a primitive species of arachnid into the Weavers, an advanced civilisation that could produce silk, intending to have them maintain her rule. The Weavers eventually turned against Grand Mother Silk and created the Citadel, which would play a magical song used to keep the higher being dormant. They lured pilgrims to the Citadel to have them continue the song, but learned that it could not be sustained forever. Failing to find a way to eliminate Grand Mother Silk, the Weavers abandoned the kingdom. Some of the Weavers left Pharloom for the kingdom of Hallownest, with one of them eventually giving birth to Hornet.
Hornet eventually reaches the Citadel, learning that nearly all of its inhabitants, including the veiled bugs, are possessed by the Haunting. She infers that Grand Mother Silk is beginning to awaken, and has manifested the Haunting as a way to control the minds of Pharloom. She defeats Lace, who is revealed to be a creation of Grand Mother Silk that she considers her daughter, and confronts the monarch at the apex of the Citadel. Depending on the player's actions throughout the game, multiple endings can be achieved. One involves Hornet defeating Grand Mother Silk and taking her place as monarch, while another results if Hornet defeats her while infected with a parasite, which manifests and kills them both. Alternatively, if the player performs a number of wishes and other objectives, a third ending is unlocked. Hornet gains the service of a bug called the Caretaker and his family of Snail Shamans, who create a trap designed to kill Grand Mother Silk. Hornet activates the trap, which summons a destructive power called the Void. Grand Mother Silk falls into the Void followed by Lace, who betrays her mother and saves Hornet at the last moment.
If the player reloads their save file after the third ending, they can continue playing. Hornet learns that Pharloom is under attack by creatures controlled by the Void, and she descends into its source in an area called the Abyss. She learns that Grand Mother Silk is still alive and using her power to protect Lace from a sea of Void, and as a result the Void is taking control of the Haunting. Hornet resolves to descend into the sea to ensure Grand Mother Silk dies before the Void fully destroys the kingdom. She works with the Snail Shamans to acquire the Everbloom, a flower used to resist the Void, diving into the sea using it. She defeats a Void-possessed Lace, and Grand Mother Silk uses her remaining power to help Hornet take an unconscious Lace to safety. The Void destroys the Everbloom, but the protagonist from the original Hollow Knight appears and saves the two, causing the Haunting and Void to disappear from Pharloom.