Shadow Keese (5e Creature)
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Tiny fiend, unaligned
Bite. Melee Weapon Attack: +4 to hit, reach 5 ft., one target. Hit: 3 piercing damage plus an extra 3 (1d6) necrotic damage
Having been warped by the presence of Twilight, a keese that resides in Twilight becomes a creature of the dark. Though it has lost the elemental power of its light world bretheren, a Shadow keese has a little more resilience and hits a little harder.
Mindless Assault. Although keese have some sense of self-preservation, they are extremely aggressive even against foes many times their own size, and will seek to take down any foreign creature that enters their territory.