You gain a +1 to your AC while not wearing armour. You can use a shield and still gain this benefit. You also gain resistance to Fire DMG.

You are able to charge your weapon attacks with the blistering heat of the Under!Fell. As a Bonus Action, you can engulf your weapon or fists in flame. For 30 seconds, all unarmed strikes, melee and ranged weapon attacks deal an extra 1d6 Fire DMG on top of the attack’s base DMG. You can do this a number of times equal to your CON Modifier. Also, you learn one cantrip that deals Fire DMG, chosen when you select this species. If the cantrip can deal multiple damage types, you may only deal Fire DMG when casting it in this way. You use your CON Modifier for the attack and DMG rolls of this spell.