True Shapeshifter

You have mastered the use of your innate shapechanging ability, allowing you to take on the features of the forms you take.

In order to use this feature you must examine the anatomy of a race you can use your Shapechanger trait to change into. You spend 1 hour studying a member of that race, at the end of this hour you must succeed a DC 20 Wisdom (medicine) check. The specimen need not be alive, in fact if the specimen is dead and the body is mostly intact you gain advantage on the check. If you succeed you can successfully use this feature, and you are no-longer required to make a check to use this feature for that race. If you fail you can repeat the check on the same race but you need a new specimen, or you need to wait 24 hours to repeat it on the same specimen. The DC of the check is also decreased by 1 for every failed check on that race.

After successfully examining a specimen of a race, you can spend a long rest to change into that race and gain all of it's racial traits, but your ability scores stay the same. After using this feature you do not gain the benefits of the long rest, and you gain 1 level of exhaustion. While changed into another race in this way, you lose your Changeling Instincts trait, and can only use your Shapechanger trait to revert to your true form. Doing so takes 1 action and all of your racial traits revert to how they were before you used this feature.