When Sirius disappeared from the hall, Athan also disappeared from outside.
He used his soul sense to find the Puppet Lord's trail from the puppet he devoured outside and broke the barrier before entering the mainland.
Seeing that, the Puppet Lord became angry as well and left the palace to meet Athan head-on, "you will regret messing with me!"
...
When Sirius arrived beside Dreevindo, he saw Athan disappearing and frowned.
Looking at Dreevindo, he asked, "what's going on? Is he your candidate?"
Dreevindo wryly smiled and nodded, "yeah. But he is...an enigma."
Sirius frowned as he looked in the direction of the mainland, "I can't see through him, which is strange. What kind of being is he? How did he appear here?"
"I don't know, but the power he wields is quite mysterious," Dreevindo spoke with a wry smile.