Oozaru - A form of lycanthropy, Saiya-jins are affected very drastically by the moon. Once the transformation begins, there is nothing short of blowing up the moon or cutting off the saiya-jins tail that will stop it. Once completed, the gigantic ape stands at an impressive 50 feet tall and will rampage, attacking everything it can with super strength and endurance.
Thankfully, knowledge of the actual condition has increased greatly over the years and it is now known that the moon gives off rays of a sort, lunar energy classifed as "Brute Rays". The intensity of the barrage of highly unstable particles varies with the phase of the moon, reaching astounding levels with a full moon.
Raw primal emotions are loosed during this period, and for the most part, instinct rules. Thus it is that Saiya-jin's in the same tribe do not attack each other. In fact, the chieftan of these closely knit communal groupings, being a symbol of authority and power, usually retains control over the group.
However, there have been incidents in which the strongest saiya-jin has actually thrown off the overwhelming urge of instinct, and with ambitious reasoning fought the chief for his position as leader.
(Boosts strength, constituion and ki but also lowers intelligence charisma and dexterity. An armor class penalty for size is incurred, and the only energy attack usable during this period is mouthblast.)
Metabollic Synthesis - Known as the supreme warrior race, Saiya-jins may have earned their title completely from this unnatural racial ability, however, this is highly unlikely...
When knocked to within 10% of his/her total hp, or brought back from the dead, a saiya-jin's overall combat efficiency takes a sharp turn down upgrade lane.
The principle is much akin to that of muscle growth. Basically, the very particles of the saiya-jins body are broken down and in the process of regrowth, a very slow process, reform in an improved fashion, just like a muscle torn apart by a workout will reform larger and stronger, so too does a saiya-jin.
Lastly, the (in)famous SSJ. Although only the strongest of the warrior race ever come close to obtaining this golden station of power, those that do are forever changed.
Initially triggered by the unrestrained power of raw emotion, Super Saiya-jin's burst into a whirl wind of golden energy that causes their hair to stand up in yellow spikes and their eyes to turn green, no matter the original color.
Super saiya-jins are definitely a force to be reckoned with, as the sizeable power increase from this transformation is astounding.
(Str, dex, con and ki increase at the cost of a high energy upkeep and a loss of charisma. At a certain point, if one's charisma is low enough, they resort to primal rage and cannot help but attack the enemy their attention is focused on with deadly abandon, stopping at nothing to kill their foe.)
-=Racial mods for saiya-jins - +2 str, +2 con, -2 cha