Bloodlines are essentially life marks interwoven with rules.
The stronger the origin strength of the bloodline's source, the higher the strength and limit of that bloodline's descendants. There are many ways of inheritance, not just through basic reproduction.
For example, the Purgatory Ancestors would demonize other beings with the Dark Demon Air, transforming them into members of the Purgatory Demon Race, or most python-like creatures would instinctively evolve toward dragons.
And whenever rules are involved, one cannot trust them completely.
Especially since this is a Primordial Beast, it is simple to alter bloodline information to deceive the Purple little dragon at the Mythical Peak.
Hence, when the Purple little dragon told it that its bloodline perception informed it that the fallen Primordial held no malice towards it, the Divinized Emperor Dragon did not fully believe it.
Even though the other party had only a bit of a 'Remnant Soul' left.
