Give me a moment to look through it...
Firstly, the armour class line should mention the +2 enhancement bonus of the mithral plate:
Armor Class:: 22 (+1 Dex, +1 deflection, +10
+2 mithral full plate), touch 12, flat-footed 21
Secondly, at level+13 his spell resistance should be 26, not 27.
Thirdly, we've messed up the feats. With 13 character levels it ought to have five standard feats, not six, and it also has to have Cleave, Improved Sunder and Power Attack because those are prerequisited for the Blackguard prestige class.
We'd better change the feats line. If we remove Stand Still and the mounted combat feats we won't need to change the attack line:
Feats: Cleave, Improved Critical (greatsword), Improved Sunder, Power Attack, Track(B), Two-Weapon Fighting(B), Weapon Focus (greatsword)
Fourthly, it's normal to list the magical items in a Possessions line, not under treasure - which also suggests we ought to modify the template's Treasure line:
Template:
Treasure: Standard (including possessions appropriate for its character level).
Sample Creature:
Treasure: Standard (see possessions).
. . .
Possessions: +2 mithral full plate, +1 adamantine dragon bane greatsword, +1 composite longbow (+5 Str), 40 cold iron arrows, 30 silver arrows, 10 adamantine arrows, boots of speed, ring of protection +1, cloak of resistance +1, wand of inflict light wounds, 134 gp
Fifthly, it has a Advancement by character class and a Level Adjustment of +4.
Sixthly, and finally, we need to spell out the ability array, e.g. add the following after the description:
The undead dragon slayer presented here is a former human with the following base ability scores: Str 16, Dex 8, Con 12, Int 10, Wis 13, Cha 16.
