For those asking "who's the guy in the hood" that saved Andrea in last night's Season Finale... the character is Michonne (pronounced ME-SHOWN)
and from this point forward is a major character within the series. Armed with a katana and the deadly skills to complement it, Michonne is an effective and crucial defender of the survivors. More info here: http://walkingdead.wikia.com/wiki/Michonne_(Comic_Series)
Michonne's introduction last night is straight out of the comics (see #TWD #19 below)!!!