What happens to the target of a "permanent" True Polymorph spell when its caster dies?

Question

The description of the spell says specifically that after the caster has maintained it's concentration for an hour, the spell can be dispelled.

The transformation lasts for the duration, or until the target drops to 0 hit points or dies. If you concentrate on this spell for the full duration, the spell lasts until it is dispelled.

In another question it was specified that spells which can be dispelled, will last until its effect ends. While spells which requires concentration, will end upon death. However it does not specify what happens with a spell that initially requires concentration.

If the caster dies after this duration, what happens to the target?

• Does the target retain its current form?
• Does the target revert back to the previous form?

Answer 1

The target does not revert; unless the spell is dispelled, it is permanent.

As the spell says after the caster concentrated for the full duration, it is there until dispelled. That means it works completely independently on the caster.

You could remove the spell by casting dispel magic on the target though.

Killing the caster does not affect the spell whatsoever after the concentration has ended as it is not the same thing as dispelling the spell.