Figured I'd add a bit of info at it.
Levels 1-7
Shadow
19 HP
12 AC
+1 AB
1-3 Dmg
1 Fort
3 Reflex
4 Will
Damage Reduction
Immunities: Disease, Critical Hits, Death Magic, Negative Level, Ability decrease, Mind spells, Paralysis, Poison, Sneak Attack
Noteworthy skills: He has 8 listen and 8 spot.
Level 8-10
Shadow Mastiff
51 HP
19 AC
+10/+5 AB
1-6 + 4 Dmg
9 Fort
7 Reflex
6 Will
It loses all immunities and Damage reduction.
It's listen and spot both increase by one point.
Noteworthy feats are Disarm, Dodge, Fearless, and Power Attack.
Level 11-14
Shadow Fiend.
55 HP
20 AC
3 AB
Attack 1: 1-6
Attack 2: 1-6
Attack 3: 1-8
2 Fort
6 Reflex
6 Will
Noteworthy feats are Alertness, Cleave, Dark vision, Dodge, and Power Attack
He now has 13 spot, and 13 listen.
Damage Immunity increased for Cold, Electrical, and Fire.
Immune to Disease, Critical hit, Death Magic, Negative level, Ability Decrease, Mind Spells, Paralysis, Poison, Sneak Attack
Level 15-20
Shadow Lord
65 HP
22 AC
8 AB
Attack 1: 1-8 +5
Attack 2: 1- 8 +5
Attack 3: 2-12 + 5
3 Fort
7 Reflex
9 Will
Noteworthy feats are Alertness, Cleave, Dark vision, and Power Attack
He now has 12 spot, and 14 listen.
Damage Immunity increased for Cold, Electrical, and Fire.
Immune to Disease, Critical hit, Death Magic, Negative level, Ability Decrease, Mind Spells, Paralysis, Poison, Sneak Attack.