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

Reflective Body.  Any time Cain is targeted by the magic missile, a line spell, or a spell that requires a ranged attack roll, roll a d6.  On a 1 to 5, Cain is unaffected by the spell.  On a 6, Cain is unaffected, and the effect is reflected back at the caster as if Cain had cast the spell, making the caster the target.

Blighted Form.  Any non-magical plant that comes within a 30 foot radius sphere centered on Cain begins to wither.  If the plant remains in the sphere for 2 rounds it dies.  A plant creature that enters the sphere on a turn or starts its turn there must make a DC 15 Constitution saving throw or take 11 (2d10) necrotic damage.

Multiattack. Cain makes two slam attacks.

Slam. Melee Weapon Attack: +7 to hit, reach 5 ft., one target. Hit: 19 (4d6 + 5) bludgeoning damage.

Reflect Weapon Damage.  When Cain is hit with a melee or ranged weapon attack from a non-magical weapon, Cain can reduce the damage to itself to 0 and inflict the original damage back onto the attacker.