Mamoru Kusanagi, or Kusanagi as he is usually called - the guy with green hair, orange skin, cat-like eyes and an over developed sense of invincibility.   His first name literally means guardian in Japanese, but you very rarely hear anyone call him by his first name.  He is usually referred to as "Kusanagi" which also has significance in the Kushinada legend: Kusanagi no Tsurugi, a sword with the name "Grass Cutter.  Kusanagi has no home nor family. 
    He was enslaved as a child by Yamata no Orochi who killed his parents, priests of a Shinto shrine, and then charged Kusanagi with protecting Kaede, the Kushinada.  He served the Aragami well, until he thought that they had killed Kaede, and then he rebelled against them, seeking revenge and freedom from them.  So he set out to kill the other Kushinada, Kaede's twin, Momiji.  He traveled all the way to Izumo, but was followed by Orochi and instead of killing Momiji, he found himself protecting her.
     Kusanagi seems to enjoy irritating Momiji, about her underwear, especially and is not too bright when it comes to understanding how she feels about him.
  Since he is part plant, it would be impossible to guess what his blood type is, but it's safe to say that it contains chlorophyl and carotenoids (the orange, red and yellow pigments that are present in fall colors).
     If you want to take a stab at guessing his blood type anyway, click here for a list of blood types to see which best suits his personality.
    His zodiac sign is another toughie, since we really don't know how old he is.... but the zodiac characteristics can be found here