Ji Lutian naturally didn't have any Divine Stones.
He had already given the only Divine Stone he had to Zhou Shu.
Even with Ji Lutian's status and cultivation, he only had one Divine Stone. From this, it was apparent that the Divine Stone was indeed extraordinary.
When he was forging the Celestial Thearch Sword, Zhou Shu had actually used the Divine Stone.
This was his first time trying to forge a grotto-heaven divine weapon. Luckily, he succeeded.
It was precisely because he had succeeded that his understanding of grotto-heaven divine weapons had improved.
Originally, he thought that as long as he had a Divine Stone and successfully forged a grotto-heaven divine weapon, there would naturally be a few worlds inside the grotto-heaven divine weapon.
But now he realized that things weren't that easy.
The function of using a Divine Stone to forge a grotto-heaven divine weapon was, in a sense, as a placeholder.