Can polymorph be dispelled?
A permanent magical effect can be dispelled unless the spell explicitly clarifies that it cannot be. True Polymorph fits into this category, which means that it can be dispelled.
Can true polymorph be dispelled after it becomes permanent?
True Polymorph isn’t permanent, as in you cannot ever dispel it or avoid suppressing it, because it remains an active spell with a duration and ending qualifiers.
Can true polymorph be dispelled after an hour?

Spells last for their full duration unless they require concentration the and spellcaster loses it. True Polymorph doesn’t require concentration after 1 hour.
Can you true polymorph into a Shapechanger?
True polymorph has no effect on a shapechanger.
Can you cast spells true polymorph?
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. The target’s gear melds into the new form.

Can you use true polymorph to become younger?
Yes you can. The spell never makes any specific claims about the age of a creature, only its challenge rating.
Can you true polymorph yourself into a dragon?
Yes you can true polymorph into an ancient brass dragon As you say, the spell and rules are clear. An ancient brass dragon is a creature, it is not a shapechanger (and may not matter if they were), and it is of the appropriate CR for your level.
Can you true polymorph a dragon?
Can a dragon cast true polymorph?
That is probably an oversight, but no. If you polymorph a dragon it loses all its features. You have to earn that spell though, through high saves and legendary resistances. Polymorph says ” The spell has no effect on a shapechanger or a creature with 0 hit points.”
Can true polymorph make you immortal?
No. Polymorph changes your body, which is unrelated to your class. They would keep whatever class levels they have in their new body. Though some abilities might not function in an unusual body.
Can you true polymorph into a gold dragon?
This means that when polymorphed into an Adult Gold Dragon, you can only do what the Gold Dragon can do, and the Gold Dragon does not have spellcasting. This is actually the case with all but one exception for adult dragons.
Can chromatic dragons Shapeshift?
You can certainly homebrew Change Shape as an ability for chromatic dragons: dragons are magical creatures. Dragons are large reptilian creatures of ancient origin and tremendous power.
Can you twin crown of stars?
RAW: Yes, Crown of Madness can be Twinned.
Can a simulacrum be true Polymorphed?
RAW: Yes, the Archmage can regain spell slots. The simulacrum’s statistics are replaced by those of the Archmage it is true polymorphed into.
Can you cast true polymorph on a Tarrasque?
No, this will not work This effect applied to your situation would polymorph your two level 15 PCs into two of the same monster but they would still be separate monsters of CR 15 or lower. Twinned spell applies the effects of the spell to two targets but does not change the spell’s text.