Because this technique has low side effects. After all your not going to die every day and with this technique. If you are pushed to the state of possessing others to survive.
Then the Undying Soul Arts technique is the only one in the completed soul arts that is best suitable for him. After deciding on the technique Wang Wei concentrated on the Undying Soul arts.
As the thousand contribution points decreased from his panel and a notification appeared before his eyes.
[ Beep Beep Unknown incoming Information reaching towards the host. Does the host want to receive it or reject it? ]
For this Wang Wei replied promptly to the Ai " Recieve the information. "
[ Receiving information... ]
Then he got a token with Undying Soul Arts written on it. When he touched the black colour token with his spiritual will he got the message from it explaining.