Prior to this, Su Zimo controlled Dao Fires of the Immortal, Buddhist and Fiend Daos. The Southern Mingli Fire was a Dao Fire that represented the Demon Dao.
Coupled with his Essence Spirit Fire, he could condense a killing move of the Pancadhi Dao Fire!
Therefore, when the Vermilion Bird Heavenly Fire descended, Su Zimo secretly condensed the Immortal, Buddhist and Fiend Dao Fires to defend against it.
At the same time, the Southern Mingli Fire slowly came into contact with the Vermilion Bird Heavenly Fire and he comprehended the difference between them.
The protection from the Dao Fires of the three Daos was naturally only one reason why Su Zimo was so confident.
Another reason was because he was protected by the Grade 12 Creation Green Lotus!
Even if the Vermilion Bird Heavenly Fire truly seeped into his bloodline, it would be extinguished by the Grade 12 Green Lotus bloodline!