I believe I understood that the Neverwinter Nine Magus ("N9M") is dormant content from the game, presumably a "magey" version of the Neverwinter Nine ("N9")that maybe magey PCs in the single player campaign could've tried out since you're best buds with Nasher there.
PnP hasn't got "N9" nor "N9M", these were purely invented for the NWN2 game, and one of them for whatever reason was not active in the final product, though it could always be switched on. Dozens of splatbooks each with their "Warrior of Bladereach" level of niche PrCs, and no one ever did N9/N9M... heh. I won't take Wikipedia for gospel, but it was neat to see some D&D nerd out there seems to have curated a list:
http://en.wikipedia.org/wiki/List_of_prestige_classes
Anyhow, Spellguard is a PnP PrC (one with clear d4 hd too). Its key attributes are "you can do things the mythal normally prevents if you've got your token that gets bound to you when you join" (conjurations, fire spells, useful only within Silverymoon), and "you can be a little more selective about AoE spells to prevent collateral damage" (useful anywhere, including fireballing your own party and choosing to only affect, say, undead or something underrepresented in your party).
Selective offensive spells would probably be a trip to try and technically implement. It would be amazing as well. SR in a radius, less hard but also kind of super-amazing. Reminds me of good old warlocks, where the "escape immediately!" type power of flee the scene (invisible/dimdoor) becomes "battle like monsters" when implemented as plain old haste. I guess SR would be sort of like a % chance of avoiding AoE effects, which if peasants were super near to you, they'd luck into non-roasty situations.
Anyhow, I assume people either have PDFs or can find PrC descriptions wherever, here's an ugly cut and paste which I found on some site for someone's homegrown world, I can't tell if it's word for word transcription from a pdf, but all the key points seem correct... just for reference if people are checking things out and have novel ideas on how to implement things.
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Spellguard of Silverymoon
As the bastion of civilization in the savage North, the city of Silverymoon attracts a great deal of attention from the fell creatures that inhabit the snow-shrouded forests. Evil giants, trolls, dark elves, and creatures of an even fouler bent scheme to make the Gem of the
North fall. Fortunately for the Silvaeren, the city is well defended against such threats. The Spellguard, Silverymoon’s elite cadre of battle-trained arcane spellcasters, protects the city against the threat of hostile magic and aids the Knights in Silver against more mundane threats.
Sorcerers and wizards are the most likely characters to become spellguards. At present, there are no bards in the Spellguard, but
there is no reason why such a character might not join the organization. Multiclass characters are rare in the Spellguard, but fighters and rogues with levels in arcane spellcasting classes are sought after for their versatility in the field. Having levels in this prestige class implies at least a nominal degree of military service in Silverymoon. Thus, the class might not be appropriate for all campaigns.
<BROKENBONE NOTE: I CAN'T CUT AND PASTE TABLES FOR SHIT>
Level BAB Fort Ref Will Special Spells per Day/Spells Known
1st +0 +0 +0 +2 - +1 level of existing arcane spellcasting class
2nd +1 +0 +0 +3 Metamagic feat +1 level of existing arcane spellcasting class
3rd +1 +1 +1 +3 Selective spell +1 level of existing arcane spellcasting class
4th +2 +1 +1 +4 Metamagic feat, spellguard +1 level of existing arcane spellcasting class
5th +2 +1 +1 +4 Selective spell (multiple types), spell power +1 level of existing arcane spellcasting class
REQUIREMENTS
To qualify to become a spellguard of Silverymoon, a character must
fulfill all the following criteria.
Alignment: Any nonevil.
Region: Silverymoon or Silver Marches.
Skills: Concentration 8 ranks, Spellcraft 5 ranks.
Feats: Combat Casting, any one metamagic feat.
Spells: Able to cast 4th-level arcane spells.
Special: The candidate must be accepted into the Spellguard.
CLASS SKILLS
The spellguard of Silverymoon’s class skills (and the key ability for each skill) are Concentration (Con) , Craft (Int) , Decipher Script (Int) , Knowledge all skills, taken individually) (Int) , Profession (Wis) , Spellcraft (Int), and Spot (Wis). See Chapter 4 of the Player’s Handbook for skill descriptions.
Skill Points at Each Level: 2 + Int modifier.
CLASS FEATURES
All the following are class features of the spellguard of Silverymoon prestige class.
Weapon and Armor Proficiency: Spellguards of Silverymoon gain no proficiency with any weapon, armor, or shield. Armor check penalties for armor heavier than leather apply to the skills Balance, Climb, Escape Artist, Hide, Jump, Move Silently, Sleight of Hand, and Tumble, and double the normal armor check penalty applies to Swim checks.
Spells per Day/Spells Known: When a new spellguard of Silverymoon level is gained, the character gains new spells per day (and spells known, if applicable) as if he had also gained a level in whatever arcane spellcasting class granted him access to 4th-level spells before he added the prestige class. He does not, however, gain any other benefit a character of that class would have gained (bonus metamagic or item creation feats, bard or assassin abilities, and so on), except for an increased effective level of spellcasting. This essentially means that he adds the level of spellguard of Silverymoon to the level of whatever other arcane spellcasting class granted him access to 4th-level spells, then determines spells per day, spells known, and caster level accordingly.
If a character had more than one arcane spellcasting class that granted access to 4th-level spells before he became a spellguard of
Silverymoon, he must decide to which class he adds each level of spellguard for the purpose of determining spells per day and spells
known.
Metamagic Feat: At 2nd level and again at 4th level, the spellguard may select any metamagic feat he does not already have as a bonus feat. He must meet any prerequisites for a feat in order to select it.
Selective Spell (Su): Spellguards are specifically trained to minimize collateral damage when casting their combat spells. Once per
day per point of Intelligence bonus (minimum once per day), a spellguard of at least 3rd level may designate a single type (and
subtype, if desired) of creature when casting a spell. When a single creature type has multiple subtypes, the spellguard may choose to
count only one of the subtypes or all of them, at his discretion. At the spellguard’s option, that type of creature is either the only type
affected by the spell or the only type unaffected by it. Inorganic material, objects, and anything else that does not have a creature
type is affected normally. Casting a selective spell requires a fullround action.
For example, suppose a spellguard is patrolling the forest around Silverymoon with a party of Knights in Silver made up of two
humans, an elf, and a dwarf. Suddenly, the group is rushed by goblins. The spellguard uses his selective spell ability to cast a fireball,
designating humanoid (goblinoid) as the only creature type affected. The fireball detonates in the midst of the melee, and although the
spellguard’s companions are within the area of the spell, they are spared any ill effects.
At 5th level, the spellguard may designate multiple creature types and subtypes for a selective spell. Each type or subtype so desig-
nated, however, uses up one additional use per day of his selective spell ability.
Spellguard (Su): The Spellguard was originally formed to protect High Lady Alustriel from personal attacks. Though that purpose
has largely become secondary to defending the city, spellguards still receive some training in serving as bodyguards. At 4th level, the
spellguard of Silverymoon may cast any personal-range defensive arcane spell on another character with a touch. For this purpose,
a defensive spell is one that improves AC, increases a saving throw modifier, or grants additional hit points (either by healing wounds
or by bestowing temporary hit points).
Spell Power (Ex): At 5th level, the spellguard’s effective caster level increases by 1 for the purpose of determining level-dependent
variables and making caster level checks.