I'm curious as to what options people are aware of for scaling effects based on the user's hit dice. The bard has a fairly unique ability at level 9 in Pathfinder: Inspire Greatness, a performance that adds two temporary d10 HD to each party member.
Furthermore, the recent Sorrowsoul bard has a fairly high level ability (12) to add +1 HD to Inspire Greatness, at the cost of targeting only himself and double the performance rounds.
An example of an ability that is empowered by bonus hit dice is the Vishkanya's Toxic ability, with DC based on HD. I'm unclear as to whether temporary HD increases affect abilities imparted by Eldritch Heritage and similar effects.
Maybe you should first flip the question around. Instead of asking what scaling effects there are, ask where do your HD count?
Answer: spells. Color spray, blasphemy/holy word/dictum/word of chaos, sleep, deep slumber, etc.
Extra hit dice are defenses against these things. Though admittedly, IIRC a few traits do specifically give bonuses up to your hit die maximum.
There is also the dazing touch ability of the charm domain.
The intent here is to proactively make use of hit dice increases using abilities such as Toxic. Becoming harder to affect with Blasphemy/Holy Word/random cleric domain powers is nice, but not the point of this thread.
Most VMC abilities scale with hit dice. that might be an alley to explore.
I'm curious as to what options people are aware of for scaling effects based on the user's hit dice. The bard has a fairly unique ability at level 9 in Pathfinder: Inspire Greatness, a performance that adds two temporary d10 HD to each party member.
Furthermore, the recent Sorrowsoul bard has a fairly high level ability (12) to add +1 HD to Inspire Greatness, at the cost of targeting only himself and double the performance rounds.
An example of an ability that is empowered by bonus hit dice is the Vishkanya's Toxic ability, with DC based on HD. I'm unclear as to whether temporary HD increases affect abilities imparted by Eldritch Heritage and similar effects.
Not just Toxic, any snake/spider familiar with poison. Poison is HD based.
Someone who would majorly benefit from this is SoP characters, since everything of theirs is controlled and tied into their CL, and that is limited by their HD. Their casting, their abilities, their DCs, everything.
Next, Gestalt characters. If you are targeting yourself only with this then it would get extra milege with a gestalt character, and more potential with a group of gestalt characters.
Iterative Attacks. The level you get this (9th) means that if you give it to the party Barbarian you then can boost their BAB to +11, and they get an additional attack.
A lot of special abilities have scaling DCs based on your level so classes that have an often used special ability, such as a Bad Touch cleric (with auras like the Madness Domain), Barbarian Rage Powers, Alchemist Bombs, Witch Hexes, and more. For these characters it is basicaly a free Ability Focus.
Basically;
Spell DC=10 + 1/2 spell level + Casting Ability mod.
Ability DC=10 + 1/2 Char Level + Ability Mod.