The Monster Manual says the following with regard to Demons and True Name:
Though demons all have common names, every demon lord and every demon of type 1 through 6 has a true name that it keeps secret. A demon can be forced to disclose its true name if charmed, and ancient scrolls and tomes are said to exist that list the true names of the most powerful demons.
Let's suppose that you use "Summon Greater Demon" to summon a demon, and then successfully cast "Charm Monster" on the demon while you still have control of it (i.e., the demon has not had a successful saving throw to break control).
Could you compel the demon to tell you its true name under these conditions?
The Monster Manual says the following with regard to Demons and True Name:
Though demons all have common names, every demon lord and every demon of type 1 through 6 has a true name that it keeps secret. A demon can be forced to disclose its true name if charmed, and ancient scrolls and tomes are said to exist that list the true names of the most powerful demons.
Let's suppose that you use "Summon Greater Demon" to summon a demon, and then successfully cast "Charm Monster" on the demon while you still have control of it (i.e., the demon has not had a successful saving throw to break control).
Could you compel the demon to tell you its true name under these conditions?
Yes. As that lines up with “a demon can be forced to disclose its true name if charmed”
The Monster Manual says the following with regard to Demons and True Name:
Though demons all have common names, every demon lord and every demon of type 1 through 6 has a true name that it keeps secret. A demon can be forced to disclose its true name if charmed, and ancient scrolls and tomes are said to exist that list the true names of the most powerful demons.
Let's suppose that you use "Summon Greater Demon" to summon a demon, and then successfully cast "Charm Monster" on the demon while you still have control of it (i.e., the demon has not had a successful saving throw to break control).
Could you compel the demon to tell you its true name under these conditions?
Yes. As that lines up with “a demon can be forced to disclose its true name if charmed”
Blank
Seems legit.