To communicate with Nell, there are two directions. One is for He Ao to enhance his own soul and power. As long as he becomes powerful enough to cross vast time and space, he can establish a connection with Nell.
The good news is that this connection should be very stable, but the bad news is that if He Ao could boost himself that much, he wouldn't have to think about how to contact Nell; he could just hold the Wheel of Stars and the Starlight Silhouette and confront them directly.
The other 'direction' is to strengthen his 'mysticism connection' with Nell and create a 'shortcut' through some special connection across time and space.
Much like the connection between the War God and Nell.
With He Ao's own power, opening such a shortcut is naturally impossible.
He Ao gazed at the dissipating red light before his eyes, but he could make use of the already existing 'shortcut.'
