Embracing your Yakfolk heritage you gain the following benefits: 

• Increase your Charisma score by 1, up to a max of 20. 
• Gain resistance to cold damage

• Possess Yak: One Yak that the yakfolk can see within 5ft. Must succeed on a DC 13 Charisma saving throw or be possessed.
  While possessing a yak, the yakfolk disappears along with all of its belongings. 

  While possessed, the yak is incapacitated and loses control of its body. The yakefolk now controls the body. The yakfolk can’t be targeted by any attack, spell, or other effect, and it retains its alignment, Intelligence, Wisdom, Charisma while possessing the yak. It otherwise uses Yak's statistics. 

  The possession lasts until the yak’s body drops to 0 hit points, the yakfolk ends the possession as a bonus action, or the yak is forced out by dispel evil and good or a similar spell. When the possession ends, the yakfolk reappears in an unoccupied space within 5 ft. of the yak. 

  Once the possession ends, the yakfolk must take a long rest before they can use the ability again.