Did you notice the two weird things surrounding the lantern? Those are bear traps which the lantern was meant to highlight, but it's possible they don't show up properly, I had a lot of problem setting them up during development, but on my end they work (Tested on Chrome and Firefox). If you can't see them still, you can still grab the lantern, make sure you have 3 hearts because the bear trap deals 1 and a half hearts of damage, then you would've to return to the NPC, but picking up the lantern spawns more bear traps since you're meant to use the lantern to make them show up.

The question mark is the mandatory symbol, you need to unlock it and it'll make perfect sense once you do. Once unlocked, you can use the spell to kill the player character (whilst keeping his gems intact) and make him respawn at the beginning of the game.

You need to interact with an inanimate object to unlock the spell, I want to add an arrow or something to highlight stuff you can interact with in the same vein as Zelda Ocarina Of Time, but it's not there yet, so if something sticks out from everything try to press on space to see if it does anything.