Super Saiyan Blue II (Also referred to as Advanced Super Saiyan Blue, Higher Super Saiyan Blue, SSB2 and Super Saiyan God Super Saiyan 2) is an advanced transformation and the highest transformation any Saiyan will ever receive. Goku is the first to unlock this ability by training in the Higher Dimensions, before confronting Black Goku for the final time.
SSB2 is infact a very unique transformation. The process requires controlled amounts of anger and full concentration of ki. Losing anger or concentration will cause the Saiyan to revert back to a Super Saiyan Blue. However, taking this into consideration, this triumphant form is the ultimate body of power, and this is shown from the immense sound effects radiating from Goku's punches. Each attack is filled with raw and focused godlike energy. Not even Lord Beerus could comprehend it's power.
The Advanced Super Saiyan Blue transformation occurs when a Saiyan has trained their godlike ki fully in the Higher Dimensions, a place which allows the gods to focus and train their energy. The transformation consists of the Original Super Saiyan 2 form colliding with the newest Super Saiyan Blue form. However, the sound that radiates from the Saiyan's body is shattering. One punch sparks a colossal thunder effect.
Power-wise, Goku as a SSB2 is far stronger than Black Goku (Immortal Super Saiyan Rose). During the episode, Goku seemed to be at a much higher level than the evil gods.
During Goku's fight with Black, Goku punches a rip into the space-time continuem, causing the Dead Zone to appear. SSB2 Goku manages to use a Kamehameha to push Black Goku into the Dead Zone. However, Black pulls Goku in with him.
Inside the Dead Zone, Goku re-encounters Garlic Jr, another immortal being from Goku's past adventures. Goku continues to fight Black and begins to lose focus, thus reverting back to a Super Saiyan Blue. Black begins to pummel Goku into the furthest depths of the Dead Zone. Goku blocks one of his attacks and delivers a new attack known as the Spirit Orb, a miniature with great spiritual power, which accurately hits Black's abdomen. This causes Black to implode from the inside. Despite Goku's attempts, Black's immortality prevented the full attack.
Goku draws all his focus to his SSB2 and re-ignites it. He then lunges at Black, grabbing the Time Ring from his finger and placing on himself. Goku then punches another rip into the Dead Zone which leads back to Earth. The two talk and Black charges at Goku. Our righteous Saiyan kicks Black back down to the lower levels of the Dead Zone, and Goku escapes.
Just before the portal closes, Black Goku re-emerges out of the Dead Zone. Goku becomes very irritant by this, and his Super Saiyan Blue 2 form becomes just as powerful as ever. Goku decides to finally finish him off by using a technique which grants him some of Zeno's power. Goku uses this power formed in an attack known as the Zeno Burst.
Such an incredible attack destroys Black's immortality, killing him.