@Dimple Taehyungie
Spoiler!
The child that he's referring to is Aileen. And yes, he is a regressor and it took him 7 years to finally witness Aileen brought to him alive due to the trial given to him and since he survive those 7 long years, he finally managed to see Aileeen alive again and took revenge to those people who cause her to die in their past life.