Roster Blerb

[Ander]

If its sole purpose is self-destruction, make it entirely different from Kaio Ken. Having elements similar to (even if not exact) a trainable move will make for confusion and blurred lines. No, if it's not Kaio Ken, you don't have to train under King Kai, but change the name and don't have any similarities with the actual technique.

The ONLY time a saiyan would ever transform by "full moon" would be during a staff-run saga where it is explicitly allowed by the staff. Otherwise, people could just role-play "well, it's a full moon" and that completely removes the purpose of having a controlled technique. So yes. In order for YOU to be able to use it, you need to wait the required time.

Oosaru - This is one of the trademarks of the saiyan race. Those native to Vejita-sei are taught the ability to create a "false moon." This false moon can be used to trigger the transformation into a giant ape-like beast, similar to the natural transformation created from a full moon. Saiyan will find that without further training, they cannot calm their mind to focus on their task, and will find their strength increasing.
Requirements: Two Weeks Training on Vejita-sei
Multiplier: x5 Ki
Attribute: Berserk
Species: Saiyan

Oosaru (Trained)- While the boost in strength is helpful under the Oosaru transformation, the drawback is that, while transformed, a person loses all control of their actions. They revert to a primal beast, looking only to destroy what's around them. After further training, however, a saiyan can learn to control the primal urges that fill their mind, removing the "Berserk" Attribute and taking full use of their power.
Requirements: Two Weeks Training on Vejita-sei, Oosaru
Multiplier: x10 Ki
Species: Saiyan

Untrained Oozaru, you are unable to control yourself in the form. With trained, you can.