[Shadow Stranger]

This post will be updated as fresh information comes to hand.

The file has 372 entries, each of 340 characters. 166 of the characters are always zero.
The first 22 are the monster name in ordinary letters.
Column 23 is the type of monster. Some types are very tightly defined, 2 = Undead and 4 = Vampires (in this game Vampires are not "undead"). While other types are amorphous grab - bags.
Column 25 is the number used in D6NPC.dat, this file seems to be connected with dialog as far as I can tell.

77 thru 107 seems to be the listing of the various resistances:
77 = Magic, 79 = Fire, 81 = Mind, 83 = Paralysis, 85 = Death, 87 = Petrification, 89 = Cold, 91 = Wind, 93 = Earth, 95 = Poison, 97 = Elements, 99 = Dispel, 101 = Silence, 103 = Light, 105 = Charm, 107 = Mavin.
A lot of the undead and vampires have at least some Dispel resistance.

Column 177 contains the “mdl” number, abstracted from line 26521 of Deep6.exe, starting with hm.mdl naturally. They can also be inferred from the first column of D6Monsnd.dat.

189 thru 220 are clearly the attacks, this can be confirmed because the numbers used are already known from D6Item.dat. (In the latter file the attacks are listed as "items"). There are seven entries, each of four characters, the last two characters are the item number of the attack, the number used in D6Item.dat.

Column 335 seems connected to 177.