Although not sure why, the Book of Knowledge speculates that perhaps it has to do with the special circumstances he encountered during his ascension to True King, and Rod later learned that during his ascension, Trolian encountered an extremely powerful black tide, which thankfully was severed by Alan in time, or the consequences would have been unimaginable.
The strength of this black tide was immense, at least at the Quasi-King Level, and although Alan hadn't stepped into the Primordial, he had ignited many Fire Sparks and possessed dozens of complete Root Origins, his absolute combat power was not inferior to a Quasi-King, thus he was able to block it. Rod was puzzled though, if this black tide appeared influenced by the Primordial God, its strength wasn't high, at least much weaker than what he encountered in the consciousness space.
