Succubi in legend are female demons which descend on dreaming men to seduce them and have intercourse with them so that they may drain their life force. In the Seiken Densetsu series they are simply female Vampires.
In SD3 Carmillas are classified as Undead.
Carmilla live in the Moonreading Tower. They float like the other Seiken Densetsu Vampires. Their main attack is swiping with poisonous claws. They can cast a character seeking Drain Kiss on your characters as well as use their very provocative “Tehehe pffpfft” attack to drop your Max HP by 20%. Their claws can be used to cast Moon Sabre.
These red clad Carmillas are found in the Mirage Palace and the Dark Castle. They have double poison swipes, and instead of a Deadly Kiss they have a Bloody Dance which will reduce your HP by an eigth regardless of defenses. Their “Tehehe, pffpfft” attack has a much larger range.
In LoM Succubus are classified as Demi-Human.
Succubus / Carmilla (J)
Carmilla returned as Succubi in LoM. They are mainly found in dark areas such as the Tower of Lieres. According to the game this clan of Vampires looks down on others. They attack with their claws and will use their “Sexy Moan” attack to shoot hearts out in all directions which will confuse you as well as deal damage. A Succubus named Elysia can join your party if the Fieg Snowfield has a Shade level of three. Her synchro will cause your weapons to drain HP from enemies.
Count Dovula / Draculark (J)
Count Dovula guards the Mindas Ruins. He is the leader of the Succubus Clan and the only male Succubi encountered in the series. He is also the only Succubus revealed to be able to turn into a Bat. When Teapo went looking for tea leaves in the Ruins he fell into Dovula’s lair and you had to go rescue him. Count Dovula drinks some of your blood and complains it is dirty, saying he wants to drink the pure blood of a Dove. During the fight with him he will cast different Shade Magics as well as bite you and summon Bats to swarm the room. For his special move Dark Rain he will fly to the top of the room and cause black rain to fall on you.