Homebrew, Ravenloft: Denizens of Darkness (3.5e)
Ethereal Sight. The akikage can see 60 feet into the Ethereal Plane when it is on the Material Plane, and vice versa.
Incorporeal Movement. The akikage can move through other creatures and objects as if they were difficult terrain. It takes 5 (1d10) force damage if it ends its turn inside an object.
Sneak Attack (1/Turn). The akikage deals an extra 7 (2d6) damage when it hits a target with a weapon attack and has advantage on the attack roll, or when the target is within 5 feet of an ally of the akikage that isn't incapacitated and the akikage doesn't have disadvantage on the attack roll.
Sunlight Weakness. While in bright light created by sunlight, the akikage has disadvantage on attack rolls, ability checks, & saving throws.
Undead Nature. A ghost doesn't require air, food, drink, or sleep.
Multiattack. The akikage can make two Freezing Strikes as an action.
Freezing Strike. Melee Weapon Attack: +6 to hit, reach 5', one target. Hit: 5 (1d4 + 3) force damage and 7 (2d6) cold damage. The targeted creature must succeed on a DC 14 Constitution saving throw or be stunned until the end of its next turn.
Shadow Blend. While in dim light or darkness, the akikage becomes invisible, along with anything it is wearing or carrying. The invisibility lasts until the akikage uses a bonus action to end it or until the akikage attacks, is in bright light, or is incapacitated.
Any Climate; Any Terrain