The viper and the river

In a chaotic universe filled with otherworldly demons, two demon slayers: Iguro Obanai, the Serpent Hashira, a skilled demon slayer who's recognized as a mysterious figure possessing great battle and destructive opportunities and he's also known for his sharp tongue, not afraid to state the truth. While Giyuu Tomioka, the Water hashira, is a distant man but has skills in battle, has a strong sense of loss and regret. Regardless of their opinions on each other things get managed to get along after several unexpected turns of events, regret, guilt and anger who were bottling up inside both of them.