Lesser Demon

Lesser Demons are a low level classic demon, more powerful than a Tiny Devil and less powerful than a Devil. The first Lesser Demon that appeared in a Castlevania game was called Leviathan in the North American localization of Castlevania III: Dracula's Curse.

Castlevania: Symphony of the Night
The Lesser Demons from Symphony of the Night are able to summon allies. The first such demon encountered is a boss demon which can summon a Mudman, a Slinger or an Ectoplasm. Lesser Demons encountered later on will only summon other Lesser Demons.

Castlevania: Harmony of Dissonance
A reimagined version of this demon, named Pazuzu, appears as a boss of the Castle Top Floor in Harmony of Dissonance.

Castlevania: Curse of Darkness
Lesser Demons return in Curse of Darkness, once again as a lesser enemy. Unlike their Symphony of the Night counterparts, these do not summon other monsters. Instead, their attacks consist of swooping in and swatting the player, as well as spiraling toward the player (Spirit of Fuji can be stolen from it whenever this attack is performed by one). They also, for some reason, will drop a Lollipop.

Castlevania: Lords of Shadow 2
An Old God called Leviathan also appears in Lords of Shadow 2. He serves as a Titan battle before the final confrontation of the game.