Cinematic Cataclysm is an cutscene addon to a very popular and cool mod L_Ender's Cataclysm by L_Ender that adds a lot of fleshed out bosses.

I was...maybe the first one who utilized cutscenes in modded minecraft in my Qliphoth Awakening mod, so i just thought that giving cutscenes to another boss mod will be a good idea.

As of now Cinematic Cataclysm adds cutscenes to 5 L_Ender's Cataclysm bosses, such as Scylla, Maledictus, Leviathan, Ancient Remnant and Ignis.

Link: https://www.curseforge.com/minecraft/mc-mods/cinematic-cataclysm