Krobus

Krobus is the only friendly monster the player can meet in Stardew Valley, though he still considers other monsters to be his friends. He is a shadow person who lives in the Sewers and is available both as a merchant and, if the player is unmarried, as a roommate. Once the player obtains the Rusty Key, Krobus can always be found in the Sewers.

Krobus' Shop is open all day, every day, including festival days. His stock is split between fixed items and rotating daily items. Fixed stock includes Void Egg, Void Essence, Solar Essence, Sign Of The Vessel, Monster Fireplace, Stardrop, Crystal Floor Recipe, Wicked Statue Recipe, Butterfly Powder, Wizard Catalogue, and Return Scepter. Rotating stock includes Slime on Monday, Omni Geode on Tuesday, Fish or Magnet on Wednesday, Mixed Seeds on Thursday, Iridium Sprinkler on Friday, Cooked Dishes on Saturday, and Bat Wing on Sunday.

Krobus is a unique social character because his tastes are much broader than most villagers. He universally loves Diamond, Iridium Bar, Monster Compendium, Monster Musk, Pumpkin, Void Egg, Void Mayonnaise, and Wild Horseradish. He likes most universal liked gifts, with the exception of Life Elixir and most cooking items, and he is neutral toward most eggs, fruit, and milk, except for Void Egg and a few special cases. He dislikes most universal disliked gifts, including Life Elixir and most cooking, and he hates most universal hated gifts, with a few exceptions such as Monster Musk, Seafoam Pudding, Strange Bun, and Void Mayonnaise.

He is rarely seen interacting with other villagers. Krobus dislikes dwarves, explaining that a thousand-year war between the dwarves and his people recently ended, and he believes the dwarves would send an assassin if they knew where he was. The Wizard is aware of Krobus' presence and prevents conflicts.

Krobus also plays a role in a few quests. During Dark Talisman, he opens the force field blocking the passage to the Mutant Bug Lair after the Wizard requests his Magic Ink. In A Winter Mystery, a shadowy figure who may or may not be Krobus gives the player the Magnifying Glass, allowing Secret Notes to be collected. After reaching 3 hearts, he mails the player the Dark Sign recipe.

If the player is not married, giving Krobus a Void Ghost Pendant lets him move into the farmhouse three days later as a roommate. He adds a room to the right of the bedroom, does not use the space behind the farmhouse, and on rainy days stands on the front porch. In multiplayer, he stays inside the Cabin on rainy days instead. He behaves much like a spouse in many ways: at 13 hearts he gives a Stardrop, and he can change wallpaper or flooring and add furniture. However, the relationship remains platonic, he never gets jealous, there is no ceremony, he cannot have or adopt children with the player, and he does not do chores. He can also be evicted for free through the book in Mayor's Manor, after which he becomes silent and refuses gifts. The Dark Shrine of Memory can erase his memories in the same way it can for an ex-spouse.

Krobus has several special dialogue behaviors as well. He remains silent on Fridays out of respect for Yoba, though he will still speak under certain circumstances such as rain, first meeting, certain quest moments, or when receiving the Void Ghost Pendant or the Stardrop at 13 hearts. He does not attend movies on Fridays, and if the player tries to give him a Movie Ticket then, he appears puzzled. While he claims not to sleep, he can fall asleep during movies other than Mysterium.