Abyssal Devil
The final Demon-type enemies, these horrors are improved versions of the Abyssal Devils. Although they lost the Painful Wind skill that made them so dangerous, their stats are nothing to scoff at, not to mention their moveset also expanded by a large margin: aside of the Skewer attack, they can also use Chaotic Slice, which hits a party member seven times; Overdrive, which increases their already-high stats even further; Volcano, which hits all party members four times; and Demon Combo, which hits a single party member six times.
As it can be seen, all their attacks hit multiple times and can be hard to block due to this, so it's advisable not only to pay attention, but also, to try to charge up a Song Magic or Super Move to try and kill them as fast as possible, as they can cause a large amount of damage to the player's party if the battle gets drawn out for too long.