From Destinypedia, the Destiny wiki
Trove Guardians can appear in specific locations at the Archer's Line, Anchor of Light, and Hellmouth areas on the moon. They will always come armed with a Cleaver, and will charge towards you to slash upon being provoked. After killing the Knight, the player will be given a message reading "The Trove Guardian has fallen, and a pathway has opened". This indicates that you have been granted the ability to spot, when close by, and traverse the hidden, floating platforms located near to where the Knight spawned. These platforms will lead to a secret chest which you can obtain loot from, as well as the notes of Toland, the Shattered: a crucial item which is required for the Memory of Toland quest. Your ability to see and stand on these platforms, however, will dissipate in time, so must move quickly to reach the chest.
List of appearances