Elsa
As a fictional character, Elsa exists in a curious state of conditional immortality. Within her narrative, she demonstrates remarkable resilience, surviving frozen hearts, raging seas, and the Northuldra wilderness. Disney's intellectual property protections ensure her continued commercial existence for at least 95 years following creation, potentially extending indefinitely through copyright renewals.
However, fictional characters require cultural relevance to maintain existence. Many beloved characters have faded from collective memory. Elsa's longevity depends entirely upon continued human interest.
Time
Time has existed since the Big Bang, approximately 13.8 billion years ago, and physicists project it will continue for at least 10^100 years before potential heat death scenarios. It has survived every extinction event, civilisation collapse, and cosmic catastrophe without the slightest interruption. Time witnessed the formation of the first stars and will observe the evaporation of the last black holes.
Unlike physical entities, Time cannot be destroyed, frozen, or meaningfully impeded by any known force, including cryokinetic magic.