Marker of Heroism Pros: - Cons: It's not really needed. It doesn't even work. It drops way too much. It stacks only one. It clutters up your set up inventory and when you need to have free space in all tabs you need to drop 16 of these with all the "are you really really sure" boxes. E: Reason why these arent even really needed is that in the valley of heroes JQ the pillars don't even kill you.
They seem to drop from the Phantom Trees in the forest. They're meant to be so that, if you have them, you can use teleporters in the Valley of Heroes to get around the Menhir JQ and get to CWK easily. Nobody really goes to CWK though, so having the pillars and the Markers fixed wouldn't do very much.
Hero's Marker of Heroism for Heroes that emanates Heroism for use of the Heroic Statues in the Valey of Heroes! 
They are a fairly common drop from Leprechauns. Their one redeeming feature is that you can NPC them (albeit only for 100 mesos each).