Final answer:
The Fire-eaters called for immediate secession to protect and preserve slavery.
Step-by-step explanation:
The Southern faction that called for immediate secession was the Fire-eaters. These were radical pro-slavery politicians who advocated for the secession of Southern states from the United States in order to protect and preserve the institution of slavery. They believed that secession was necessary to maintain their way of life and political power.
Learn more about Southern faction's call for immediate secession