Classic Monsters Revisited: The Shade (MMII)

The Shade first appeared in the AD&D Monster Manual II. It's a curious entry as it's more of a template than an individual creature. The shade is supposed to be built on the chassis of a leveled NPC by simply adding abilities and features to the existing numbers. For extra complexity, the shade's abilities and features vary according to light conditions.

There's a lot of moving parts to this monster. After figuring out the shade's original statistics in life, the DM then has to consult two separate tables in the monster's description to calculate its current scores and powers, which can be altered mid-battle as light conditions change. 

Typical of late-1e and 2e materials, the shade's description suffers from a "wall-of-text" that hides an interesting monster concept behind a lot of superfluous, often-contradictory detail. I'm using this monster in Moormist Manor, but I want to break the original shade down to its core components and then rebuild it into a more-interesting monster for AD&D (plus a 5e version because I haven't decided which ruleset I'm using yet).