At the chasm, Yasova's family finds the hedron cocoon that shields Ugin. Baishya follows his call and enters a trance; Naiva can share its memories through contact with her sister. Those memories show Ugin returning to Dominaria and confronting the wars Nicol has made between their dragon siblings and their peoples.
A seeming familiar visitor draws Naiva toward a different account. Bolas presents his brother as a jealous deceiver, casting his own pursuit across planes and killing in the Meditation Realm as justified retaliation. His certainty does not make the account impartial. It shows how thoroughly he has made wounded pride into an explanation for everything he does.
The ancient death in the Meditation Realm is not the same event as Tarkir's later cocoon. What survives within the hedrons can communicate through memory; the family protects that enduring essence without reducing Yasova's uncertainty to a simple declaration of bodily life.