Lucífer

What? You never knew the whole story behind finding Waldo? Sure! "Where's Waldo?" was about a fictional character named Waldo, who had been murdered! 

As the reader you played the part of someone who cared and wanted to find Waldo so badly that when peering into crowds you only think you see Waldo as much is the case when someone you care about mysteriously goes missing, you start to see them everywhere you go.

This is how the books are played out, selling them as a children's book is easiest way to not explain ridiculous happenings, why else would you find the guy in such a variety places? They're usually summer vacation hotspots, which further proves my point that you are playing a person who cared a lot for Waldo even when you tried to take summer vacations to put your mind at ease you could do nothing more than see Waldo everywhere you went which is common for people trying to come to grips with someone no longer coming back.

Waldo is dead.