The boy on the boardwalk at Victor Park, presumably Liam.
Liam is the name of the deceased child for which the Victor Park playground was built. Very little is known about Liam, as we only know that he died under mysterious circumstances, and that his mother petitioned for the playground to be built in his memory.
Speculation
- It is possible that Liam was somehow connected to The Observer and The Slender Man, as when the Observer was asked if Liam had anything to do with him or his keeper (This was at the time when Noah was in stasis after the Nature Trail), The Observer replied by saying he was not allowed to say.
- A picture of a boy standing at the boardwalk next to the Slender Man is a reoccurring theme in the series, seen in Box Analysis and COMECLOSER. It is possible that this may in fact be Liam.