The Trust Betrayed
The phylactery recovered from Naxxramas was delivered to Father Inigo Montoy at Light’s Hope Chapel. The place represented resistance to the undead. Entrusting the vessel to a priest there seemed to place the unfinished task in friendly hands.
Montoy instead returned it to the Lich King. Kel’Thuzad could regain his form because the means of preserving him had survived the very expedition meant to stop him. The betrayal turned the recovery of a dangerous object into the condition for another campaign.
Montoy’s betrayal left Kel’Thuzad’s phylactery beyond the victors’ control.

