Can't wear armour - 'cause it's a freakin' beaver!

Naturally Stealthy - You can attempt to hide even when you are obscured only by a creature that is at least one size larger than you.

Fey ancestry, due to the fey inhabiting their arm. You have advantage on saving throws against being charmed and magic can’t put you to sleep.

Nimble - You can move through the space of any creature that is of a size larger than yours.

Keen Smell - has Advantage on Wisdom (Perception) checks that rely on smell.

Hold Breath - can hold its breath underwater for 15 minutes

Can understand Sylvan - speak, read, and write.

Can understand common - speak and listen only, unable to read and write.

Primary ability score increase +2 : Dexterity, it's a small nimble beaver that can scurry around quickly.

Ability score increase +1 : Constitution

You have superior vision in dark and dim conditions. You can see in dim light within 60 feet of you as if it were bright light, and in darkness as if it were dim light. You can’t discern color in darkness, only shades of gray.

Can understand and communicate with small beasts

Natural Armour, base Armour class 13