added this as a bonus action:
Beguile. Baalphegor targets one creature she can see within 30 feet of them and who can see her. The target must make a DC 18 Wisdom saving throw. On a failed save, the target uses their reaction, if available, to move up to their speed to a location chosen by Baalphegor, then either makes a melee attack against a target of Baalphegor’s choice or falls prone (Baalphegor’s choice). Creatures who can’t be charmed automatically succeed on this saving throw, and creatures who have advantage on saving throws against being charmed make this saving throw with advantage.
The normal 5E approach would be to just have the attack cause the charmed condition.
I'd also make the range a bit longer than 30 feet. It might also be worth considering adding it as a Legendary Action option too.
The save DC is strangely low. Isn't this a Charisma-based ability like her
Innate Spellcasting? With her stats, Baalphegor should have DC 24 with such abilities.
That's probably too far the other way though (i.e. too high).
The standard for a Challenge 21 creature is DC 20, so it shouldn't be
too far off that number.
Glasya has CHA 26, giving her Cha-based spell-like DC 23, but that's also a bit too good for CR 21 too going by the Calculator. Indeed, I suspect that Glasya would be under-CRd if we ran her through that device.
So, something like:
Beguile #2. Baalphegor targets one creature she can see within ## feet of them and who can see her. The target must succeed at a DC 24 [?] Wisdom saving throw or become charmed until the start of the next turn. A charmed target uses their reaction, if available, to move up to their speed to a location chosen by Baalphegor, then either makes a melee attack against a target of Baalphegor’s choice or falls prone (Baalphegor’s choice).
Another possibility is giving her a Beguiling version of Glasya's
Confusion Aura as a defensive measure, like so:
Beguiling Aura. Any creature hostile to Baalphegor that starts its turn within 20 feet of her must make a DC 24 [?] Wisdom saving throw. On a failed save, the creature is charmed for 1 round, as if affected by the charm monster spell. On a successful save, the creature is immune to Baalphegor's Beguiling Aura [and Beguile?] for the next 24 hours.
Hmm, that "next 24 hours rule should probably apply to
Beguile too:
Beguile #3. Baalphegor targets one creature she can see within ## feet of them and who can see her. The target must succeed at a DC 24 [?] Wisdom saving throw or become charmed until the start of the next turn. A charmed target uses their reaction, if available, to move up to their speed to a location chosen by Baalphegor, then either makes a melee attack against a target of Baalphegor’s choice or falls prone (Baalphegor’s choice). On a successful save, the creature is immune to Baalphegor's Beguile [and Beguiling Aura?] for the next 24 hours.
What do you think?