It was when they arrived at the Wellspring.
Eren who saw the beautiful waterfall was mesmerised but what truly caught his attention was the stone platform on which the two disc-shaped tiers of carved rock lay, as if an altar of some kind.
Yet the altar was clearly missing something – the altar stood vacant, leaving an empty space at its center that seemed to yearn to be filled, a void waiting to be made whole once more
Eren felyt as if he knew what was missing, he was attracted to the the platform more so than ever.
He could hear the Master Vihaan talking about something but his attention was wholy attracted towards the stone platform and as if guided by something, Eren started to walk forward.
The first to notice him was Erza. She squinted her eyes looking Eren.
Then attention of everyone including Master Vihaan turned to him.