Xuanwu used a sword.
But "Bodhisattva" had never expected her to actually draw out an Azure Dragon Sword.
The lotus platform she occupied was also vital, but it was meant to support life; the Azure Dragon Sword was for battling enemies...
If anything in the Four Symbols was the greatest restraint to her current form, the Azure Dragon came second, and the first was actually the Vermilion Bird.
One signifies life, the other death.
However, the current Vermilion Bird had not yet achieved the meaning of the master of death contained in the star chart; she was still contending with the understanding of fire known to the masses, otherwise, Maitreya over there would have been annihilated in an instant.
Nevertheless, what Xuanwu drew out was the true Personal Divine Sword of the Ancient Azure Dragon! That vigorous vitality, with just a slight contact, nearly crushed her, almost leaving her unable to muster any strength.
