Actions

Multiattack. The banshee makes two attacks; two reaping scythe attacks, or one reaping scythe and one icy wind attack.   Reaping Scythe. Melee Weapon Attack: +8 to hit, reach 5ft., one target. Hit: 14 3d6+4 necrotic damage. A creature hit by this attack has its hit point maximum reduced by an amount equal to half the damage taken.   Icy Wind. Ranged Spell Attack: +8 to hit. The banshee extends her hand, conjuring a blast of freezing air that hits every creature in a line 5ft. wide and 30ft. long. Each creature hit by this attack takes 7 2d6 cold damage and has its movement speed decreased by 10 feet until the start of the banshee's next turn.   Horrifying Visage. Each non-undead creature within 60 feet of the banshee that can see her must succeed on a DC 13 Wisdom saving throw or be frightened for 1 minute. A frightened target can repeat the saving throw at the end of each of its turns, with disadvantage if the banshee is within line of sight, ending the effect on itself on a success. If a target’s saving throw is successful or the effect ends for it, the target is immune to the banshee’s Horrifying Visage for the next 24 hours.   March of the Dead. Up to six undead within 60 feet of Lathria and can hear her can use its reaction to move up to half its speed.   Wail (Recharge 5-6). The banshee releases a mournful wail, provided that she isn’t in sunlight. This wail has no effect on constructs and undead. All other creatures within 30 feet of her that can hear her must make a DC 13 Constitution saving throw. On a failure, a creature drops to 0 hit points. On a success, a creature takes 10 3d6 psychic damage.

Bonus Actions

Dirge. As a bonus action, Lathria can perform a dirge that lasts until the start of her next turn. Lathria can select from one of three effects:

1. Song of Horror. Provided Lathria isn't incapacitated, an enemy that starts its turn within 60 feet of Lthria and can hear her must succeed on a DC 16 Wisdom saving throw or become frightened until the end the start of its next turn. If a creature's saving throw is successful, the creature is immune to Lathria's Song of Horror for the next 24 hours.
2. Song of Sorrow. Provided Lathria isn't incapacitated, an enemy that starts its turn within 60 feet of Lathria and can hear her must succeed on a DC 16 Wisdom saving throw or start wailing and weeping in grief until the start of its next turn. Until this wailing and weeping ends, the target can't take actions or reactions, and its speed is halved and can't be increased. If a creature's saving throw is successful, the creature is immune to Lathria's Song of Sorrow for the next 24 hours.
3. Song of the Profane. Provided Lathria isn't incapacitated, any undead that starts its turn within 60 feet of Lathria and can hear her gains advantage on melee attack rolls and saving throws against features that turn undead.