I was taught that Christ assumed or clothed his humanity to the Divinity. He is sometimes called Son of God while Son of Man(Humanity). You are thinking humanity is another personality of God. We believe in three.
No, I am not saying humanity is another personality of G-d. The church teaches God the father, God the son and g-d the holy spirit. I am stating that the church also teaches the hypostatic union, God the son is 100% god and 100% man. Therefore within the trinity, is humanity. So the Christian form of God is 3-in-1 plus humanity, so maybe not a Quadrinity but more acurately a Bi-natured Trinity. Regretably...heretical.