Diamrem (5e Creature)
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Medium monstrosity, unaligned
Fish Juice. Whenever the diamrem takes slashing or piercing damage, all creatures within 5 feet of it must make a DC 12 Constitution saving throw, becoming poisoned on a failed save; a creature can remake this save at the start of its turn, ending the effect on a success. While poisoned this way, creatures are charmed by the diamrem and will use their reaction to intercept melee attacks targeting it if they are within 5 feet of either the diamrem or the creature attacking it; when they do, the attack is made with disadvantage and hits the intercepting creature if it would have hit otherwise but missed due to the disadvantage.
Multiattack. The diamrem makes one slam attack, and either attack with an argulus or use its Juice Splatter.
Argulus. Ranged Weapon Attack: +5 to hit, range 30/60 ft., one creature. Hit: The Target becomes poisoned by the diamrem's Fish Juice; additionally, while poisoned this way, the target takes 7 (2d4 + 2) poison at the start of its turn, before making its saving throw.
Juice Splatter. Ranged Weapon Attack: +5 to hit, range 20/40 ft., one target. Hit: The target becomes poisoned by the diamrem's Fish Juice if it is a creature. Each creature in a 10 foot radius, including the target, must make a DC 12 Constitution saving throw, taking 7 (2d4 + 2) poison damage on a failed save, or half as much damage on a success.
Slam. Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit: 15 (3d6 + 1) bludgeoning damage.
These creatures sometimes emerge from the parasitized brood-hosts of junjo. Far rarer, the diamrem is also much faster, deadlier and more intelligent than its cousins.
Variant: Dead Fish
Sometimes diamrem can be created by necromantic magic, or rise from the dead through other means. These diamrem have the undead type, are vulnerable to radiant damage, and replace half of any poison damage they deal with an equal amount of necrotic damage.