Sasami Masaki Jurai (柾木 砂沙美 樹雷, Masaki Sasami Jurai) is a key character in the Tenchi Muyo! metaseries as well as the protagonist of her own various non-canonical spinoffs.
In the Tenchi continuities, Sasami is the younger sister of Ayeka and so is also a princess of the planet Jurai. Within the Masaki extended family, Sasami usually takes on the dual role of younger sister/mother. She may be the most responsible of the group and takes care of all the cooking duties. She has a rarely-seen mischievous streak within her, however, and takes great delight in fooling the older girls.
Sasami has teal-colored hair usually tied in long pigtails with melon pink eyes. In the Tenchi continuities, Sasami also has an upside-down triangle birthmarked on her forehead, as a symbol of her status as Juraian royalty.
Sasami has appeared in every Tenchi Muyo! series, as well as/including several spinoffs based around her as the central protagonist. In almost every incarnation her personality, background, primary outfits, relationships, and abilities change. In some incarnations, her art style is altered more than others, though her basic coloring and structure remaining the same.
Sasami has a huge fan following across the globe and is the inspiration for what VIZ editor Carl Gustav Horn called 'The Sasami Effect', in that any young cute girl within a cast of characters will inevitably become the most popular. Possible examples of this include the Sailor Moon character, Chibiusa, plus many other "young" female characters in Japanese, French, and American series.
Sasami's personality is more mature in the OVA than in the other continuities, and more aggressive in the second TV and the Pretty Sammy spin-offs.