An Elaborate Prank.

All of them can see these lines. If a line is pointed out to them by others, then they will be able to follow the line and they will find its source or where it ends. 

Jarkon didn't care if they identified Soverick's aura so he didn't bother to help. Fortunately, there are 5 others who are enthusiastic. They helped the clueless four gain some clues about the aura. So all of them finally got hold of Soverick's aura. They became sure of it when they reached the front of the portal.

"It is certain that Soverick was here. His aura is too fresh and thick here. These traces indicate that he was here not too long ago."

"That should be impossible. Soverick has been dead for more than a hundred years. He couldn't have been here."

"But the auras are here to prove it."

"Then the auras might be fake."

"That's why we must get to the bottom of this. We will know if he is dead or not when we get more information."