After Ren dealt that devastating blow the ORIGIN had weakened immensely but not enough that he could be killed. Now there were only two incarnations of the Strongest Mortal Soul left.
One was, of course, the original incarnation the strongest of them all the one who started the system of reincarnation. The other one was Rei Kuraki who had gained the powers of all incarnations except for Ren and the original incarnation. These two were leagues above the other incarnations of the Strongest Mortal Soul which was why it wasn't so surprising that they were able to last until the end.
"Now only the two of you remain. So are you still going to foolishly fight me, or are willing to join me in the new reality I will create?"
The ORIGIN despite getting hurt so much by the incarnations of the Strongest Mortal Soul and the madness that was eroding its existence still showed benevolence to his favorite son.