SpoilerIs it explained how Ugin transports Bolas to his prison? As a non-planeswalker, Nicol should be obliterated by the Blind Eternities... Also, is that dying bit stated explicitely like that? It would go against previous lore, which made the Mending remove Planeswalker immortality (which ws the reason for Liliana's pacts and one of the reasons Bolas was so determined to regain his old status...
Out of curiosity, did Sorin feature in the novel?