Project Destiny is the term used by The Overseer to refer to a small segment of The Great Game involving four children. It is an important plot point for the Shattered Psyche Verse series of blogs Project Destiny's basic outline appears to work mostly in line with The Wooden Girl but all Fears seem capable of taking part in it. The Slender Man also appears to hold the other key role in this project.
In basic essence, the project seems to revolve around the idea of controlling the lives of humanity; setting them on a a pre-determined path. Controlling their destiny. This has so far been achieved by first exposing four children to The Fears on January 1st 2000, using The Slender Man's capabilities to shatter their minds in different and unique ways.
One of them was taken and planted elsewhere by Him, another was taken into the care of The Overseer. The final two were left where they were. The managing of their lives has continued by having spies within their friends and families to keep track of them and shift things along a desired route. This is most obvious by the events that have been happening to Adam Grayson.
The long-term goals of this project are currently unknown. Overseer claims it is a necessary sacrifice to provide a unifying peace for everyone. But no matter what the goal; the project clearly is an experiment by them to see if they can control mankind for better or worse.