This is Kao Ninjaratzu in a super form known as Saiba Kao. The form is generated by Kao fusing with his granddaughter/guardian angel Saiba and gives him near deity like powers. Generally this form is used when Kao needs to take down something super massive that would otherwise require deity like strength, without calling on the Goddesses themselves, but in later points, he eventually learns how to unlock the power himself, at the cost of Saiba Crystals slowly draining if Saiba herself is not present.
1. When Kao turns to Saiba Kao, he gains the same colors as Siberia. Initially he thought it was a coincedence, but after he combines his soul with Kao Ratzu, he then understands why he looks this way.
2. In this form, Kao doesn't have full control over his body. It's very much like Dragon Ball Z fusion in that both Saiba and Kao are controlling Kao's body at the same time. Because of this, every time Kao fuses with Saiba, he tends to act surprised and seems almost dazed until he gets used to the new form and immense power. He is in complete control when he transforms himself though.
3. Saiba Kao's voice also changes from his somewhat deep and whispery voice to kind of hearing both Kao and Saiba's voice at the same time.
4. Though it's Kao and Saiba fused, it's Kao's body. Saiba is only taking a bit of control.
