Saiya-jins are a race of people identical to humans except for their unique prehensil tail and their usual hair styles. When a Saiya-jin see's the light of the full moon they transform into an Oozaru self(were-monkey). After transforming into their Oozaru selves their power-levels increase 10 fold,and their sense of smell,hearing and eye sight increase drasticly. Saiya-jins also have a lust to fight and to grow stronger. When Saiya-jins have a near death experience and recover the get much stronger. Another quality Saiya-jins have is the ability to transform into the mythical Super Saiya-jin. This state can only be achieved for the first time by becoming very angry once a Super Saiya-jin for the first time it is now very easy to do it for a second,thrid and then so on etc. But once a Super Saiya-jin they have distinct qualities for each level of the Super Saiya-jin each level stronger than the previous. Here is a listing of the qualities of each level and who has achieved each level of the Super Saiya-jin:

Super Saiya-jin Levels :Super Saiya-jin Super Saiya-jin UltimateSuper Saiya-jin 2Super Saiya-jin 3Super Saiya-jin 4
Description:Light Golden Yellow Hair,turquise eyes,25% increase in body sizeGreenish Yellow Hair,Double Super Saiya-jin Body Size,no pupilsLonger Golden Yellow hair,50% increase in body size,light turquise eyesDrastic increase in hair length Dark Golden Hair,pale turquise eyes,75% increase in body sizeBlack Semi-long hair,Golden eye color,Burgundy red fur,tail grows back
Achieved :

Freeza's is a unique individual. To my knowledge I only know of two more of his kind King Kold his father, and Koola his brother. Before Goku Freeza thought he was the being in the universe except for of course his father and brother. I think Freeza is of lizard origination because of the tail but that's only and opinion. Here is breif description of each of Freeza's form's:

Freeza's Forms :Freeza's 1st Form Freeza's 2nd Form Freeza's 3rd FormFreeza's 4th FormFreeza's 4th Form 100%
Description :Small with straight black horns very short,and wears saiya-jin type armor.Much taller than form 1,has longer curved upward horns very muscular and looks alot like King Kold.A little shorter a long cylindrical head with 3 sets of horn,looks alot like a demon also a very small face with sharp teeth.Medium height slim,body is mostly white with purple padded muscules,and a long white tall.Them same as form4 except much more muscular and gets a little taller.

Koola simalar to his brother can transform as well unlike their father King Kold. Koola first form looks pretty much like Freeza's last form at full strength. But Koola's 2nd and final form looks very cool he triples in size grows some white chest armor and wrist bands as well as legs bands his head gets big looks like a bull except with multiple horns and also has a cool retractable face mask to see Koola transform go to my Clip Archive and veiw the clip intitled Koola transforms!

Cell is a unique individual as exactly like Freeza. Cell is a combination of Saiya-jin,Nameckian,Human,Freeza's race and multiple other races making him the perfect fighting machine. He was made inside a sort of tude from cell's of the different races therefore we have his name Cell.

Cell's Form's :Cell's 1st Form Cell's 2nd Form Cell's 3rd Form
Description :Cell's first form looks flat out ugly,he looks like a cross between a frog and a demon.Cell's second form look taller because he absorded C-#17Cell's Final form is Perfect Cell because he absorbs C-#18 he looks exactly like his 2nd form, but he kinda has a white tint.

If any of this info is incorrect please feel free to email-me!