Per dndbeyond rune knight page, the stone rune description is this:
Stone Rune. This rune’s magic channels the judiciousness associated with stone giants. While wearing or carrying an object inscribed with this rune, you have advantage on Wisdom (Insight) checks, and you have darkvision out to a range of 120 feet.
In addition, when a creature you can see ends its turn within 30 feet of you, you can use your reaction to invoke the rune and force the creature to make a Wisdom saving throw. Unless the save succeeds, the creature is charmed by you for 1 minute. While charmed in this way, the creature has a speed of 0 and is incapacitated, descending into a dreamy stupor. The creature repeats the saving throw at the end of each of its turns, ending the effect on a success. Once you invoke this rune, you can’t do so again until you finish a short or long rest.
per the conditions page, incapacitated description is this:
Incapacitated An incapacitated creature can't take actions or reactions.
My question is: do attacks against the incapacitated created at advantage like the unconscious condition? Nothing in the rules/description says the attacks are at advantage but it seems like it should given they are in a "dreamy stupor" .
No. Incapacitated means exactly what is says and no more - no actions or reactions. An incapacitated creature could still move though this specific effect states their speed is 0 so they won't be moving.
So no advantage on attacks against the incapacitated creature and no effect on saving throws made by the incapacitated creature. However, the incapacitated condition does end concentration on any spells so if the affected creature was concentrating on a spell, that spell ends.
Per dndbeyond rune knight page, the stone rune description is this:
Stone Rune. This rune’s magic channels the judiciousness associated with stone giants. While wearing or carrying an object inscribed with this rune, you have advantage on Wisdom (Insight) checks, and you have darkvision out to a range of 120 feet.
In addition, when a creature you can see ends its turn within 30 feet of you, you can use your reaction to invoke the rune and force the creature to make a Wisdom saving throw. Unless the save succeeds, the creature is charmed by you for 1 minute. While charmed in this way, the creature has a speed of 0 and is incapacitated, descending into a dreamy stupor. The creature repeats the saving throw at the end of each of its turns, ending the effect on a success. Once you invoke this rune, you can’t do so again until you finish a short or long rest.
per the conditions page, incapacitated description is this:
Incapacitated
An incapacitated creature can't take actions or reactions.
My question is: do attacks against the incapacitated created at advantage like the unconscious condition? Nothing in the rules/description says the attacks are at advantage but it seems like it should given they are in a "dreamy stupor" .
No. Incapacitated means exactly what is says and no more - no actions or reactions. An incapacitated creature could still move though this specific effect states their speed is 0 so they won't be moving.
So no advantage on attacks against the incapacitated creature and no effect on saving throws made by the incapacitated creature. However, the incapacitated condition does end concentration on any spells so if the affected creature was concentrating on a spell, that spell ends.
What David said
Rules in D&D tend to be like wedding vows in The Princess Bride. If it doesn't say it, it doesn't do it :)