True Polymorph with More Self-Buffs?

[dragoeniex]

Our party is halfway through level 18, and as this is the highest level most of us have played, some interesting spell interactions have begun rearing their heads. My hexbard, for example, picked up True Polymorph as his first ninth level spell. The first uses of this were cast on other party members as health buffers or the start of an underwater kaiju fight.

My first self-cast for this came a couple rounds after I'd used Crown of Stars (magical secrets). With the ruling it only made sense for the stars to stay up, we ended up with a dragon flying around with bonus action lasers. Pretty rad!

I'd like to make sure this is kosher, though. Shapechange specifically lets you retain your class features so long as the new form is capable, which is why SC has a leg up on self-casts over TP. TP does not allow you to cast your own spells while in-form. Additionally, TP says the target's game statistics are replaced by the new form's.



Resulting question: Do spell effects stay active when a buffed character TPs? And followup, does it matter whether the (non-concentration) buff was self-cast?

Logical continuation: If this works, the heck happens if you Mirror Image before True Polymorphing? Illusory, 15-foot tall Balors dancing around? Or would the Mirror Image stay according to the form you'd originally cast with, making it funny but irrelevant unless you popped back out of form?

[TheTeaMustFlow]

Resulting question: Do spell effects stay active when a buffed character TPs? And followup, does it matter whether the (non-concentration) buff was self-cast?

Yes, regardless of who cast the spell. Nothing about true polymorph states that it removes spell effects on a character, so it doesn't. Additionally, non-concentration spells, unless specifically stated otherwise, stay around regardless of the caster's condition - the (probable) loss of spellcasting capability caused by polymorphing does not negate spells used before it. (I say probable because it is entirely possible to true polymorph into a form capable of casting whatever other spell is being used.)


Logical continuation: If this works, the heck happens if you Mirror Image before True Polymorphing? Illusory, 15-foot tall Balors dancing around? Or would the Mirror Image stay according to the form you'd originally cast with, making it funny but irrelevant unless you popped back out of form?

It is unclear whether the duplicates would change to mimic your new form (I would rule yes, but it is not explicitly stated), but going strictly by RAW the spell would remain effective regardless. I would not have any issues with any DM who ruled otherwise, however.

[dragoeniex]

Yes, regardless of who cast the spell. Nothing about true polymorph states that it removes spell effects on a character, so it doesn't. Additionally, non-concentration spells, unless specifically stated otherwise, stay around regardless of the caster's condition - the (probable) loss of spellcasting capability caused by polymorphing does not negate spells used before it. (I say probable because it is entirely possible to true polymorph into a form capable of casting whatever other spell is being used.)

That's a reasonable conclusion and reasoning. I was wanting to say "Yes, of course this makes sense," but since I'm who it benefits, wanted to be double-sure on the personal bias. Thank you for the response!

I agree it's probably a DM call on Mirror Image. If it ever comes up, it's either going to be impressive-- or it's going to be three illusory bards clipping in and out of a dragon that's too big for them to circle. I can be content with either.