Shadowfeather

Spoilers ahead!

Shadowfeather is an NPC that can be found in the Nursery.

After Level 1
If the protagonist talks to Shadowfeather, she will mention her friendship with Snowflower when the two of them were apprentices. This will lead the protagonist to inquire about their father; unfortunately Shadowfeather does not possess any information. She will then go on to describe how Sandpelt quit his place as medicine cat apprentice to be her mate.

After Level 4
Talking to Shadowfeather prompts her to describe her fear for the future of her kits; specifically the threat of BoulderClan; and how she can only teach them to live with it.

One time only, if the protagonist talked to Shadowfeather at least once between Level 1 and 4, and the protagonist has Sandpelt in their party, Shadowfeather will give the protagonist 3 each of Potion III, Elixir III, and Stimulant.

After Level 9
If the protagonist received items from Shadowfeather, Sandpelt will stop the protagonist as they are about to proceed with Level 10, having discovered that Shadowfeather has been taken to the Dark Forest. The protagonist will not be able to proceed to Level 10 unless they have Sandpelt in their party. They also will not be able to complete the level unless they find and rescue Shadowfeather. Upon being rescued, Shadowfeather gives the protagonist 8 Potion III and 5 Stimulants.