Note: I have taken some liberty with the CR of this character. Because the skills he acquired as a Paladin for four levels virtually disappear (save some bonuses from being Blackguard) after Falling, I'm not counting the Paladin levels in the CR; you can bump him up a CR level or two if you feel that balances this NPC.
Galen Medici: Paladin (fallen) 4, Sorcerer (Necromancer) 6, Blackguard 1
Hit Dice: 4d10 plus 6d4 plus 1d10 (37 hp)
Armor Class: 19 (+1 Dex, +5 Armor, +3 Bracers)
Base Attack/Grapple: +7/+9
Attack: +1 Battleaxe +8 melee (1d8+3 damage)
Full Attack: Same
Special Attacks: Smite Good 1/day
Special Qualities: Aura of Evil, Detect Good, Poison Use, Lay on Hands
Saves: Fort. +7, Ref. +2, Will +5
Abilities: Str 15, Dex 12, Con 10, Int 10, Wis 13, Cha 16
Skills: Diplomacy +8, Heal +11, Hide +6, Intimidate +4, Knowledge: Religion +2, Ride +3, Sense Motive +3
Feats: (including a (B) if it is a bonus feat)
Environment: Cleave, Craft Undead(B), Improved Sunder, Power Attack, Still Spell
Challenge Rating: 7
Alignment: Lawful Evil
As the years passed, Galen grew more intrigued with the poisons and diseases he was researching, and started not only healing those who had been afflicted by these maladies, but also the beasts who carried the toxin, slaying or capturing them, and then bringing them back to his laboratory to study their poisons more closely. Originally this was in the hopes that he could discover what kept the creatures themselves from being poisoned, and hopefully use that knowledge to assist humans suffering from that disease. But one day he captured an aberration near some ancient ruins that had a toxic bite, which was also intelligent. and offered up much information about what it knew of its abyssal toxins, hoping to win its freedom by fair exchange, or trickery after it gained Galen's trust.
The thought of researching extraplanar toxins (or indeed the possibility that all toxins came from another plane) intrigued Galen and he set up the means to summon a lesser fiend to him. He acquired a scroll of Protection from Evil and hired the services of a cleric to perform the summoning. The cleric didn't get it quite right, and a non-toxic creature was summoned, but it did exchange knowledge with Galen about what it knew of toxins. The Order, when they heard, was appalled and though Galen hadn't done any spell which was Evil, technically, they suggested he get an Atonement, just for the sake of piety. He told them he would consider it, but never really did.
Though work with the fiend he summoned, Galen made a remarkable breakthrough. He learned to heal dead and dying tissue so well that it came back to life (new feat: Craft Undead). He had managed to create a zombie, not by any spell, but by sheer scientific healing (i.e. Dr. Frankenstein). Pursuing this line of work caused him to fall from his Paladin graces and be rejected from the Order for refusing to get an Atonement (he still thought he was doing Good for the people with his research). He returned to his lab, and in his grief the fiend saw its opportunity and convinced Galen to run away with him. Galen agreed and freed him, who promptly destroyed the lab and flew with Galen to the ancient ruins, where Galen continued to learn and became a Blackguard.
New Feat: Craft Undead: Prerequisites: Heal +10. Benefit: This feat allows the character to craft a zombie like the spell Animate Dead but using a process that's more like a golem construction (lesser flesh golem); it's using healing and science to bring life back to dead tissue, rather than magic. To create zombie, the appropriate body that's laid out in the Animate Dead spell description must be obtained, and prepared using 100 gp worth of healing oils, herbs and equipment. Assembling the body requries a DC 11 Heal check. The construction of a zombie requires 3 hours and takes no XP loss
Wealth level is 22,000 gold, so equipment is a +1 Battleaxe (12 + 300 masterwork + 2000 enchantment = 2,312 gp, 5 lbs.), Bracers of Armor +3 (9,000 gp), a suit of +1 Mithral Scale Mail (50 + 4,000 mithral + 1,000 enchantment = 5,050 gp; Light armor, AC +5, Max Dex +5, Check Penalty -1, Spell failure 15%, 15 lbs), a Wand of CLW (375 gp, 50 charges), a Wand of Invisibility (4,500 gp, 50 charges), and five doses of Medium spider venom (Injury DC 14, 1d4 Str/1d4 Str; 150 g each, 750 g total) for a total of 21,987 gold worth of equipment, leaving 13 remaining for misc items
Aura of Evil (Ex): The power of a Blackguard's aura of evil is equal to their class level plus their cleric level, if any.
Detect Good (Sp): At will, a blackguard can use detect good as a spell-like ability, duplicating the effect of a the detect good spell.
Lay on Hands (Su): A blackguard with a Chr. score of 12 or more can heal wounds (themselves or others) by touch. Each day, a blackguard can heal a number of hit points equal to their blackguard level x their Chr bonus (1x3 = 3). This healing can be spread out over multiple targets (all touched), or used to deal equal damage to a touched undead (no AoO given to the undead touched).
Poison Use: Blackguards are skilled in the use of poison and never risk accidentally poisoning themselves when applying poison to a blade.
Smite good (Ex): Once per day, a blackguard may attempt to smite good with one normal melee attack. They add their Chr mod (if positive) to their attack roll (+3) and deals one extra point of damage per class level (+1). If a blackguard accidentally smites a creature that is not good, the smite has no effect, but is used up for the day.
Spells (Blackguard): One first level spell per day, DC is 11 plus spell level. 1st - Inflict Light Wounds
Spells (Sorcerer): 6/7/5, DC is 12 plus spell level. Necromancer (Div and Trans banned; starred spells bonus Necro spells). 6/4/2 spells known: 0th - *Disrupt Undead (Necro; V, S), Resistance (Abjur; V, S, M), Acid Splash (Conj; V, S), Ghost Sound (Illus; V, S, M), Touch of Fatigue (Necro; V, S, M), Flare (Evoc; V), Ray of Frost (Evoc; V, S), 1st - *Ray of Enfeeblement (Necro; V, S), Cause Fear (Necro; V, S), Magic Missile (Evoc; V, S), Burning Hands (Evoc; V, S), Shocking Grasp (Evoc; V, S), 2nd - *Command Undead (Necro; V, S, M), False Life (Necro; V, S, M), Darkness (Evoc; V, M)