As he didn't have proper cultivation, it was impossible for Heavin to trigger his final tribulation. Hence, he prepared a fake body that was filled to the brim with his Mental Energy, causing it to behave like his body.
It had set cultivation thanks to the materials used to forge it at this state. As for the various law comprehensions, it was attained using the Law Cores. Honestly, they had spent a lot of resources on the creation of this body, enough to fuel dozens of Primal Gods from scratch.
Especially the Law Cores, each of them was at the Primal God Realm, the peak attainable by them. Each Law Core used in the creation of Heavin's body was enough to make any cultivator obtain the foundation necessary to reach the peak of the Primal God Realm.
Slowly, the fake body began to churn the Godly Energy within it, causing the dantian to brim in power before, eventually, tribulation clouds formed amidst the spatial storm, gradually thickening in size.