Rewinding the scenes a bit, he played a clip of Estelle and Elias' conversation.
It was all recorded.
Everything that Heine took interest on, he recorded it with his devices.
Heine kept tabs on her and lots of other people. This behavior wasn't prominent in the first years of meeting Estelle, but as time went on, his memories as 'Astarte' began to resurface.
This led him to develop a twisted mindset.
He deduced that it was the stress of having to cope with a new set of personality and memories, ones that differed quite greatly from his original belonging that ended up causing such a change.
He also began to build his own people, ones that he made sure wouldn't be able to betray him.
They were people he personally scouted. Everyone had a dark past that dragged them down, and Heine gladly played the role of a savior to make himself their 'idol'.
Someone they all are indebted to, someone they must repay.
In the end, a couple dozen followers were gathered.
