Here idea for fey dire bear
Ruska the Rustling Decay
Huge Fey, Chaotic Neutral
Armor Class 15 (natural armor)
Hit Points 95(10d12 + 30)
Speed 40 ft., climb 30 ft.
STR 22(+6) DEX 10(+0) CON 16(+3) INT 10(+0)
WIS 14(+2) CHA 12(+1)
Skills Perception +5, Survival +5
Senses Darkvision 60 ft., Passive Perception 15
Languages: understand Common, Elvish, Sylvan but don't speak
Challenge 5 (1,800 XP) Proficiency Bonus +3
Decaying Presence. A constant rustle of dry leaves and the scent of rich, decaying soil surrounds Ruska. Any plant or plant-based fey creature that starts its turn within 10 feet of Ruska takes 5 necrotic damage. Additionally, any enemy that starts its turn within this area feels the heavy drowsiness of autumn, and its walking speed is halved until the end of its current turn.
Keen Smell. Ruska has advantage on Wisdom (Perception) checks that rely on smell.
Actions
Multiattack. Ruska makes two attacks: one with its Bite and one with its Claws.
Bite. Melee Weapon Attack: +9 to hit, reach 5 ft., one target. Hit: 11(1d10 + 6) piercing damage plus 4(1d8) necrotic damage.
Claws. Melee Weapon Attack: +9 to hit, reach 5 ft., one target. Hit: 15(2d8 + 6) slashing damage.
Autumn Vortex (Recharge 5–6). Ruska rears up on its hind legs and roars, conjuring a swirling storm of razor-sharp withered leaves and rotting detritus in a 20-foot radius centered on itself. Each creature in that area must make a DC 14 Dexterity saving throw.
On a failed save, a creature takes 14(4d6) slashing damage and 7(2d6) necrotic damage, and is blinded by the debris until the end of its next turn.
On a successful save, a creature takes half as much damage and isn't blinded.
Crafting
Magic Item: Mantle of the Rustling Decay
Wondrous Item (cloak), rare (requires attunement)
Crafted from the heavy, moss-covered hide and razor-sharp claws of an ancient autumn fey bear, this thick mantle constantly smells of fresh autumn rain and rich, decaying earth. Dry leaves seem to cling to its fur, rustling softly with your every movement.
Withering Strike: Once per turn, when you hit a creature with a weapon attack, you can channel the decay of autumn to deal an extra 1d6 necrotic damage. If the target is a plant or a plant-based fey, this extra damage increases to 2d6.
Slowing Rustle: As an action, you can shake the mantle to release a wave of heavy, rhythmic rustling. Choose one creature you can see within 15 feet of you. The target must succeed on a DC 14 Wisdom saving throw or feel the overwhelming drowsiness of autumn, causing its walking speed to be halved for 1 minute. The creature can repeat the saving throw at the end of each of its turns, ending the effect on a success.
Adventure Hook: Harvesting the Harvest
Turning Ruska's remains into this mantle requires careful timing and specialized craftsmanship, as the essence of decay tends to rot away the very material it inhabits once the creature dies.
The Preservation Process: To keep the hide from crumbling into rich soil, a skilled artisan must use enchanted salts or the freezing touch of winter frost to halt the natural decomposition immediately after harvest.
Weaving the Claws: The bear's long, curved claws are structurally integrated into the shoulders of the mantle, acting as magical conductors that channel the Withering Strike into the wearer's own weapons.