Sid Orbs

Sid Orbs are collectible items that are needed to complete the LoreKeeper's weekly quests, which are unlocked after the player as beaten the game.

Appearance
Sid Orbs, as their name implies, are pure black orbs which emanate shadow and darkness, much like the person they come from. Though from afar they appear small, up close they are about as big as the player.

The LoreKeeper's Weekly Quest
Once the player has completed Journey to the Sun and has made it to the Hub World, the Lorekeeper will begin giving out daily quests which revolve around collecting Sid Orbs.

Every week starting on Saturdays, 10 Sid Orbs will be scattered across the Sun Domain and the player must collect them. When the player has collected all 10 orbs, they will receive a notification from their inventory, where their reward (a mask or pair of wings) will be waiting.

Finding Sid Orbs
Sid Orbs don't seem to have set spawn locations, however, where they will be found can be determined by the hint the Lorekeeper provides the player. This will tell you where the farthest orb will be, and thus the rest of the orbs can be found before the mentioned location.

Sid Orbs can be found on any island except for Sid's Tower and the islands after the Great Shrine.

Vetro Matt
They upload YouTube videos every Sid orb hunt, recommended if you want to save time