Duel Under Faith was a sacred battle that could be invoked by any noble knight in the presence of the sun or a high-ranking Clergyman. The duel, also called the duel of fates—was a death match. The winner takes it all, and the loser loses it all.
With honor at stake, those who refused the duel would lose respect afterward. However, considering the seriousness of the duel, it was rarely invoked to begin with. However, when invoked, it caught the attention of even the distant folks.
Sylvester, a man who upheld his honor and word in the highest regard since his youth, could never say no to such a challenge. It was something his enemies knew all too well. However, by now, his strengths had been gauged by many who died under his foot—yet, Niel initiating the duel meant the false Pope was confident in winning.