One of my favorite races through out the Zelda universe. Mainly because they are so mysterious and yet powerful.
Something tells me if it were not for the Kokiri, one of these little guys would have laid waste to the world, as they are both free to leave the Lost Woods and very fragile, needing friendship and care only the innocence of children can provide.
I say "would" because I don't count the Termina incident, seeing as that was most probably most of Majora's doing...though it is slightly hinted at that the Skull Kid knew of the dark powers of Majora and that's why he took it (though I doubt he expected to be completely taken over by it).
Why do I think they are powerful? Well, in Ocarina of Time, killing one gets you a golden rupee (200), and the stronger a creature is, the more they drop. In Twilight Princess, they can manipulate tons of puppets...and after you defeat it, it mentions it would like to play again sometime, implying that the fight was just a test and it was just playing with you. I think these little buggers have a lot of power, and if one tried to harness that power...eesh.
This Skull Kid is a hybrid of the 64 series and Twilight Princess Skull Kids. I love the garbs of the old Skull Kids, but the body of the new ones...(though it would have been cooler if their skin was black still).