Ascended Tiefling

You have undergone a powerful ritual, or consumed a special magic item in order to unlock a metamorphosis into your final form. This feat grants the following effects:

Limited Flight. Once per day you can fly for an hour. You have a fly speed equal to half your movement speed, and once you start using your fly ability, you cannot turn it off until the hour is fully done.

No Longer Human. You are now a Fiend, and are immune to the Charmed condition. You are also now immune to the damage type you naturally resist as a Tiefling.

Fiendish Dominion. You may cast Dominate Monster at will on Fiends matching the subtype of your devilish or demonic parent below CR 2, and they have disadvantage on their Wisdom saves against this spell. You can do this a number of times per Long Rest equal to your player level + proficiency bonus halved, rounding down.

Improved Element. Your spells that deal the damage type you naturally resist as a Tiefling ignore damage resistance and immunities.