Your demonic ancestry has manifested in your voice, aiding your speech. When you speak while making a Diplomacy check, you receive a +2 bonus on that check. This bonus increases to +4 if you are expert in Diplomacy, +6 if you are Master, and +8 if you are Legendary.
You can use your words to dominate the minds of others. You can cast dominate as an innate spell 1/day heightened to half your level, rounded up, as a three action activity without needing the somatic component.
You can fly through the air in short bursts at half your land Speed. If you don't end your movement on solid ground, you fall at the end of your turn. You can only gain the benfits of this feat while in your true form.
Your demonic ancestry has granted you some resistance against attacks though these can be overcome by a properly prepared opponent. You gain resistance 10 to physical damage (except cold iron).
Your demonic ancestry has granted you some resistances to energy. Choose one of the following energy damage types: acid, cold, electricity, fire, or sonic. You gain resistance 5 to that damage type.
Your demonic ancestry has granted you some resistances against spells. You gain a +4 bonus to your saving throws against magic effects. This bonus increases to +6 to saving throws you are expert in, +8 to saving throws you are master in, and +10 to saving throws you are legendary in. This same bonus applies to your saving throw DC against magic effects.
Your words flow like honey and can take on a magical quality. You can cast charm as an innate spell at-will heightened to half your level, rounded up, as a three action activity without needing the somatic component.
You can make people follow your every word. You can cast suggestion as an innate spell at-will heightened to half your level, rounded up, as a three action activity without needing the somatic component.
You unfold your wings for travel and can keep them unfolded for 10 minutes. You gain a fly Speed equal to your land Speed while your wings are unfurled. You can only gain the benfits of this feat while in your true form. If you have Enlarged Wings, you gain a +10-foot status bonus to your fly Speed with Strengthening Wings. As normal, since your fly Speed is derived from your land Speed, this status bonus isn't cumulative with a status bonus to your land Speed, if you have one.
You've studied the history of your people as well as their traditions, enemies, and skills. You gain the trained proficiency rank in Diplomacy and Religion. If you would automatically become trained in one of those skills (from your background or class, for example), you instead become trained in a skill of your choice. You also become trained in Thyllkthoron Lore.
Your Thyllkthoron affinity blends with your class training, granting you great skill with Thyllkthoron weapons. Whenever you gain a class feature that grants you expert or greater proficiency in certain weapons, you also gain that proficiency in daggers, rapiers, scimitars, shortswords, sword canes, warhammers, and all Thyllkthoron weapons in which you are trained.
You prefer finer weapons and the weapons of your people's goddess. You are trained with daggers, rapiers, scimitars, shortswords, sword canes, and warhammers.
In addition, you gain access to all uncommon Thyllkthoron weapons. For the purpose of determining your proficiency, martial Thyllkthoron weapons are simple weapons and advanced Thyllkthoron weapons are martial weapons.
You are attuned to the weapons of your Thyllkthoron ancestors and are particularly deadly when using them. Whenever you critically hit using a Thyllkthoron weapon or one of the weapons listed in Thyllkthoron Weapon Familiarity, you apply the weapon's critical specialization effect.
You can spread your wings to glide safely to the ground. As long as you can act, and you are in your true form, you take no damage from falling, no matter what distance you fall.