Bloodseeker Siren

Spellcasting. The Siren is a 10th-level spellcaster. Its spellcasting ability is Charisma (spell save DC 17, +9 to hit with spell attacks). The Siren has following Sorcerer spells prepared: 

Cantrips (at will): dancing lights, friends 
1st level (4 slots): charm person, disguise self                        2nd level (3 slots): crown of madness, disguise self

Magic Resistance. The siren has advantage on saving throws against spells and other magical effects.

Multiattack. The Siren can make two claw attacks any of which can be replaced by a sling attack.

Claws. Melee Weapon Attack: +4 to hit, reach 5 ft., 1 target. Hit: 5 (1d6 + 4) slashing damage. 

Sling. Ranged Weapon Attack: +9 to hit, range 30/120 ft., 1 target. Hit: 6 (1d4 + 9) bludgeoning damage.

Siren Song. The siren sings an alluring melody. Every humanoid or giant within 300 feet of the siren that can hear the song must succeed on a DC 17 Wisdom saving throw or be charmed until the song ends. The song ends if the siren is incapacitated.

While charmed by the siren, a target is incapacitated and ignores the songs of other sirens. If the charmed target is more than 5 feet away from the siren, the target must move on its turn towards the siren by most direct route. It doesn't avoid opportunity attacks, but before moving into damaging terrain, such as lava or a pit, and whenever it takes damage from a source other than the siren, the target can repeat the saving throw. A charmed target can also repeat the saving throw at the end of each of its turns. If the saving throw is successful, effect ends on it.

A target that successfully saves immune to this siren's song for the next 24 hours.