Charisma increases by 1. Dexterity or Wisdom increases by 1.

Due to your unique upbringing you have learned how to speak both of your parents tongues and are proficient in both. You can read, write, and speak Common, Elvish, and Infernal.

You mature at the same rate as humans, but your not sure how long you have as Elves live up to 750 years and Tieflings can live about 100. Safe to say you might not have to worry about it for awhile.

Born of both fiendish and elven blood your ability to see in dark conditions is no small ability you are accustomed to the dark stary nights and the smokey pits that resemble the hells.

Due to your Elvish blood you are harder to charm by people who seek to control you. You also have taken to meditation and find bliss in it. It takes you a little longer to feel rejuvenated than other Elves. Elves don’t need to sleep. You meditate deeply, remaining semiconscious, for 6 hours a day. As a result you are immune to spells that cause sleep from your deep meditation. While meditating, you can dream after a fashion; such dreams are actually mental exercises that have become reflexive through years of practice. After resting in this way, you gain the same benefit that a human does from 8 hours of sleep. 

You have resistance to fire damage.

Due to your Elvish lineage you have the ability to hide even when you are only lightly obscured by foliage, heavy rain, falling snow, mist, and other natural phenomena. Years of your parent teaching you their gifts has granted you good practice in their abilities as well.

You have learned some tricks from your father from his time spent in the hells.