Guild Wars 2

do I have to do everything in just one character? or if I did 50% in one char and the other 50% for another I will receive the 100% world exploration reward??

Theres two different ones. The character one obviously is character only. BUT the account one is all characters combined.

Since the achievement and progress is character bound, I’d assume this has to be done within that character.

There seem to be 2 different counters here. The one you see in the top left of the screen counts all poi’s, hearts, vistas, etc. from the entire PvE map and the entire WvW map. The counter in the achievement and on the character loading screen however seems ( I do not know this for sure) to be linked to the amount of areas discovered, and thus to the ‘Krytan Explorer’, ‘Orr Explorer’, etc. achievements right above them.
If this is so, I would appreciate it if there were to be a way to find where you were still missing those undiscovered areas. Currently I am missing 4 in Kryta but I cannot find where they are as I do have 100% map completion accross PvE.

I think Yackeroeni is right. Doing everything on the map in a zone isn’t bad because you can see on the left side what you have left and discover most of the areas at the same time. The only issue I see is if the 100% mapping uses both counters as you can’t tell how many areas there are to discover in each zone. I, myself, have 100% all of Kryta’s zones for the poi’s, hearts, vistas, skill points, and waypoints and Krytan Explorer says I still have undiscovered areas.