Can True Polymorph be used repeatedly to never age?

Question

Let's say we have a level 20 human wizard named Dumbledore. Dumbledore is wicked old. Dumbledore would like to not die of old age, as he has a few enemies left to take care of. Can Dumbledore cast True Polymorph on himself, concentrate for the full duration, and permanently de-age himself into

1. A younger version of any other creature
2. A long-lived creature (dragon, elf, etc)

And if yes to any of these, will this permanent transformation extend Dumbledore's lifespan? Would doing so permit Dumbledore to repeatedly cast True Polymorph and never die of old age?

Note: Dumbledore could obviously still die of other causes, such as Power Word: Kill cast by a talented former student.

Answer 1

Yes you can. The spell never makes any specific claims about the age of a creature, only its challenge rating.

If you turn a creature into another kind of creature, the new form can be any kind you choose whose challenge rating is equal to or less than the target’s (or its level, if the target doesn’t have a challenge rating). [PHB 283]

So you could turn yourself into an elf or similarly long-lived creature which is also a level 20 wizard.

If you wanted to turn yourself creature like a dragon with the intent of doing this repeatedly, you need to be sure to note the spell casting abilities of your new form. From the spell description:

"The creature is limited in the actions it can perform by the nature of its new form, and it can’t speak, cast spells, or take any other action that requires hands or speech unless its new form is capable of such actions." [PHB 283]

If you choose a creature that can innately spellcast (or it has hands and can speak), then this isn't a problem.

Answer 2

Probably, no

True Polymorph transformation isn't actually permanent.

RAW it is still "a creature transformed by magic", so the permanent transformation still can be dispelled, through the Dispel Magic spell or an antimagic field. When you are permanently polymorphed, a creature with Truesight can still see your true form.

All these things indicate that a polymorphed creature still has its true (but somehow hidden) form. Another evidence is that Power Word Kill affects the true form, not the assumed one.

Being polymorphed into a yonger being doesn't automatically prevent your true form from aging. RAW imply it will age, because there is no rule that says your true form resides in stasis while you are polymorphed. However, rules don't clarify this point explicitly, so I suggest to figure it out by using the general RAI idea about aging.

Can D&D magic prevent aging?

Death by old age has special meaning in D&D magic. Even the True Resurrection spell won't work:

True Resurrection
You touch a creature that has been dead for no longer than 200 years and that died for any reason except old age...

nor other spells:

Resurrection
You touch a dead creature that has been dead for no more than a century, that didn’t die of old age...

Revivify
You touch a creature that has died within the last minute. That creature returns to life with 1 hit point. This spell can’t return to life a creature that has died of old age...

The only spell that can return you from dead in this case is the rare druidic Reincarnation spell, which doesn't return your original body, but gives you a new body (hence, a new true form) instead.

The only potion that actually can make your true form younger is the Potion of Longevity, but it has special condition - you can't drink it for ever, because you will age eventually (straight away, if you're unlucky):

Potion of longevity
When you drink this potion, your physical age is reduced by 1d6 + 6 years, to a minimum of 13 years. Each time you subsequently drink a potion of longevity, there is 10 percent cumulative chance that you instead age by 1d6 + 6 years.

If no magic can easily give you eternal life, why True Polymorph should be different?

It's like the picture of Dorian Gray

Dumbledore could actually try to prolong his life by all the magic means, including the True Polymorph method. How it will ends is up to the DM.

I can suggest the Dorian Gray scenario. Dumbledore assumes an elf form and lives for 200 years. Eventually he loses the assumed form. Maybe a powerful envier casts Dispel Magic on him. All the 200 years return to his original form, turning him into an incredible old man. He died from old age right at the moment.

Answer 3

I will add this to Sam W's answer.

While the following is open to interpretation

Choose one creature or nonmagical object that you can see within range. You transform the creature into a different creature, the creature into an object, or the object into a creature (the object must be neither worn nor carried by another creature)." [PHB 283]

The intent of the spell is to turn the target into a different form whether it living or non-living. The trope that the spell derives from likewise has all manner of things and people turning into different things.

To use the spell to transform the target into a younger version of himself is a more limited use of the spell. Obviously it has benefits in terms of age but going back to the original trope, we have myths and legends where people were transformed into a statue or something and the climax occurred decades or even centuries later.

So given the level of the spell I don't see any issue with using it as a form of anti-aging. In terms of mechanics the spell wordage more concerned with CR and combat effectiveness than this type of use of the spell. On other words of all the implications of this spell the designers are concerned with somebody transforming into a say a dragon and gain all the dragon's powers than the other implication, like anti-aging.

Answer 4

The way I understand True Polymorph after research it's not just a form, you become that creature. I'm Dumbledore's case you could True Polymorph into a human, but none of the class features come with you, you are now an "average" human.

I imagine your original form, not existing while polymorphed, wouldn't age. So I would suggest becoming an adult dragon, you then have your choice of forms with dragon Shapechange, and at least 700 more years of life. If your dragon body gets too old or you gain enough xp to hit level 20, find someone to dispel True Polymorph, you change back to Dumbledore, then True Polymorph to adult or Ancient Dragon. Because adult and ancient dragons are listed differently, in this case at least, you could choose age. You do lose class features and spellcasting. I would argue though that a reasonable DM would let a dragon train as a player class. There's no reason a dragon shapechanged to humanoid couldn't learn. And honestly you'd probably be accepting a nerf anyway so why not. With 700+ years and the benefit of your memories dragon Dumbledore should be able to eclipse human Dumbledore. Just maybe take some precautions against that True Polymorph going down unexpectedly.

Antimagic fields would be dangerous. If you kept other enchantments on yourself enemies may be less likely to dispel the polymorph.

Antimagic fields would suppress the polymorph Dispel could ruin progress you'd made(?)

If you start human, Polymorph to dragon, shapechanged to elf I think True Sight would reveal human. It would be a surprise you were a dragon, even to someone with True Sight.