This page in our guide to Devil May Cry 5 contains a description of one of the bosses in the game - Urizen. Nero reaches the Demon King and wants a rematch.
Urizen in Devil May Cry 5
Where to find the boss: Mission 08 - Demon King
Urizen uses the same attacks as in the prologue. The boss is sitting on his throne - the only way to damage him is to attack the crystal levitating near Urizen. The boss can shoot a laser (jump over it), create spheres that slow you down, and shoot projectiles that fall down on the place where you are standing.
Also, the crystal can create spikes - if you get hit by them, Nero will be sent backward. Urizen can also cast fireballs at you if Nero is standing farther from him. To defeat the boss, you have to avoid his attacks and be on the move at all times. Use Gerbera to perform mid-air dodges.
Destroy the crystal and Urizen will stand up. You have to lose this fight.