Because the more perfect the Dao Heart,
the further a cultivator can travel on the path of Martial Arts,
just like Sword One of Sword King City, reputed to be capable of achieving Grandmaster status at any moment, but delays the breakthrough to hone his Dao Heart,
the Sword Spirit Qi Baiyu of the Yundong Celestial Sword Alliance is the same,
slaying Grandmasters with Fifth Realm power as easily as slaughtering dogs,
and yet he doesn't enter the Grandmaster Realm, as it is rumored he nurtures a sword that has yet to mature, his Dao Heart is not yet perfect, so he doesn't break through. The day the sword is complete will be the day he washes away the mundanity and becomes a Grandmaster!
However, this wasn't the case for Gu Zhan,
In fact, when he entered the Fifth Realm, he also perceived his own Dao,
at that moment, he stood atop a mountain,
holding a saber, gazing down upon the Human World,
If he followed that Dao, he would probably, like Qi Baiyu, nurture a saber,
