Ultimate Super Saiyan (LOTSG)

"We can still go Super Saiyan, in fact, once you've fully mastered this power you'll essentially go Super Saiyan 3, thankfully without the massive energy drain."

- Kaestos to Gohan Ultimate Super Saiyan is a transformation that is achieved after a Saiyan has gone through the ritual that the Grand Supreme Kai of Universe-K, the Old Kai of Universe-B, and Kaestos know how to perform, which unleashes an individual's full potential.

Future Trunks' enhanced Super Saiyan 2 form could be considered a sort of precursor or primitive variant of this transformation, however, it is still extremely effective. It has been referred to as Augmented Super Saiyan 2 or Penultimate Super Saiyan.

Appearance
This form looks identical to the user's Super Saiyan 2 state, but without any lightning appearing in the aura that surrounds their body.

Future Trunks' variant is essentially just a powered up Super Saiyan 2, and instead of having no electricity is has an increased quantity of it.

Usage and Power
When in this form the user gains a boost of power equivalent to Super Saiyan 3, increasing their power by a factor of 400. The form also holds little strain on one's body unless they haven't trained seriously or used it for years.

Kaestos first used some of this form's power during his fight against Mira and defeated the powered up demon (who held power equal to Super Saiyan Vegeto) in one hit.

When Demigra later appeared Kaestos fully entered this form and briefly fought with the Demon God, seemingLY able to fight on par with him; however, Kaestos quickly discovered that Demigra was holding back and toying with him.

After over 5 Million years Kaestos once more used this form, this time in his fight against Super Buu (Gotenks, Piccolo, and Ultimate Gohan absorbed) after Vegeto allowed himself to be absorbed, however, Super Buu did gain the power of Super Saiyan 2 Goku and Vegeta.

Kaestos retained relative control of their fight, and even with the problems from not using this form for some time affecting him he lasted until Super Buu was defeated from the inside out by Goku and Vegeta.

Gohan briefly entered an early version of this form when preparing to fight against Beerus, however, he quickly lost control over the transformation and reverted back to his base state almost instantly.

After the fight against Beerus concluded Gohan learned how to use this form with Kaestos' guidance, and by the time of the revived Freeza's invasion he was equal to 10% of the tyrant's mastered Final Form.

Kaestos later admitted that his Ultimate Super Saiyan form was far weaker than what it once was, and even during Freeza's second attempt to get revenge against Goku he only had 30% of the tyrant's Mastered Final Form power, he later implied that at full power he would have 120% Freeza's Final Form power, equivalent to a 1.5 on the God Ki scale.

Drawbacks
If a Saiyan hasn't used this form before or has been lax about training for a great deal of time it can rapidly drain their Ki reserves and only have half its intended effectiveness.

Kaestos first experienced this after 5 Million years of slacking off in his training during his conflict against Super Buu (Gohan, Piccolo, Gotenks absorbed w/Goku (SS3) and Vegeta (SS2) power), only managing a 200x multiplier for the majority of their fight, which only granted him twice the power of the Majin.

Gohan later experienced this when he first transformed while training with Kaestos, and had to enter it a few times in order to overcome the transformations initial problems.