Divine Seal: Reborn as Saint Cai'er's Brother

Waking up in a world of divine seals and demonic threats, he discovers he's been reborn as the older brother of the legendary Saint Cai'er. Armed with knowledge of the future and a determination to protect his sister, he must navigate deadly trials, forge alliances with legendary knights, and carve his own path to power. In a realm where humanity's survival hangs by a thread, can he change destiny itself and become the shield his sister never knew she needed?