Your Strength increases by 2

you can see up to 60ft in darkness or dim light though most Races cant define clear colors you can see colors as you are apart of the Darkness itself 

to gain the befits of a long rest or must go into a inactive state of dark mediation where the room or space darkens to where you are the lightest figure in the room or space

if anyone enters the space they see what are your true desires or flash backs from your past in the shadowfel but this is ultimately up to the Dm

dark angels are generally around 6-7ft

and weight can very between each of them

there features like hair eyes trend towards dark features but there are known dark angels with all sorts of hair colors 

you are not limited to dark features  

you have a walking speed of 30ft and 40ft flight speed

you trend towards evil because of your connection to the shadowfell this can tend to put the dark angels though great stress with they feel its not right on rare cases dark angels have broken free from there connection but this is very rare