It's clear that Chen Tang isn't joking, nor is he interested in joking with Gulan Fentian and the others...
The Great Gulan Clan and him are essentially enemies rather than friends. Apart from Gulan Fentian, previously during the Trial Starry Sky, Chen Tang even slayed another direct lineage member of the Great Gulan Clan, named Gulan Fenyue.
Both You Fenzhen and Tang Zhao from the Dongsheng Great Clan know about this, and it's impossible for them to keep it a secret for Chen Tang—they will definitely spread the word.
In that case, since his hatred with the Great Gulan Clan is irreconcilable and they wouldn't turn hostility into goodwill,
then the Great Gulan Clan sending out a Thirteenth Stage Elder Ancestor to deal with Chen Tang this time, is capable of slaying him—why not do it?
This certainly isn't a spontaneous decision.
