@SirTapTap
Every time the kitten scratches you, say "ouch!", expressing that it hurts very much. If you bleed a bit, show it to the kitty and say (don't scream) "that hurts". But do not harm the kitten or be bad towards it. The little hunter doesn't know any better.
Everyone who plays with the kitten should do the same. Keep your "claws" back as well, meaning only touch it rather softly and do not hit back in anger.
After a while, the kitten should retract the claws while playing.