The Shadowcaster is a variant form of Magic-user from the Tome of Magic sourcebook for 3.5 Edition D&D. As the name implies, it's a mage type class dedicated to the use of Shadow Magic, making it heir to the Shadow Mage kits of Advanced Dungeons & Dragons.
But basically it's relatively simple and the system prevents you from overloading yourself with too much information too quickly.
- Your character learns one "mystery" per level, so in effect at level 1 they only know a single level-one-equivalent spell (plus some the 0-level equivalents), and they may cast this mystery once per day. Meaning you are vastly inferior to an equivalent caster at level 1, sorry but true.
- Each mystery comes from a three-level "Apprentice" path, but the only way to learn the higher level mysteries is to learn two mysteries from previous levels, so therefore to learn a Lv3 mystery, you need two Lv2 mysteries and two Lv1 mysteries, and you must also learn each mystery in sequence, so you cannot jump ahead.
- Once he achieves certain milestones with caster level (7th) new "Initiate" paths become open to him, which not only provide higher level mysteries to learn from equivalent to 4th-6th level, but also enhance the mysteries known from previous paths. With all of the "Apprentice" mysteries now becoming Spell-Like Abilities and being able to be used twice per day rather than just once.
- Once he reaches 13th caster level, a final "Master" path becomes available for him, granting access to Level 7-9 spell equivalents. But the Initiate mysteries become Spell-Like just like the Apprentice were, and the Apprentice spells then become Supernatural abilities and can be cast three times per day.
So by the end of the career-path its a bit of a clusterfuck of rules. However, because of the way the class progresses, you can only know 20 separate mysteries in total, in any number of possible combinations. So you could, if so inclined, learn 20 of the 21 Apprentice Mysteries available and have no Initate or Master level powers, though this would probably be a self-nerf, though you would be able to cast 60 times per day... it goes on.
The advantages this has over a traditional caster is that the lower level abilities can still find function much later on, rather than just achieving a +1 caster level modifier (which often gets capped anyway). Particularly when your Supernatural abilities cannot be Resisted, Dispelled or Countered.
Most of the mysteries are presented "as per spell..." each with minor thematic enhancements meaning that your mysteries are mostly better than the traditional equivalents too.
There are other minor class features as you level up, such as gaining the ability to require less sleep or food to survive, Darkvision as well as accumulating more 0-level "fundamental" spells which don't scale up as you increase in level though.
You also earn bonus feats equal to half the number of paths you know mysteries from, therefore can turn up at any time. Though you WILL get one by level 2 because of the limitation on learning two mysteries of each level before progressing to the next level. One caveat to this is that you only keep learning these feats if you stay in the class so if you prestige class, then you stop gaining these feats even if you increase your mystery level elsewhere.
- That said, there is nothing stopping you returning to the Shadowcaster class if you manage to complete a Prestige class, and collect all your bonus feats in one go.
However the downside is obvious: you only know 20 mysteries: MAX. therefore you have lost your versatility over a Wizard/Cleric and know even fewer spells than more restricted classes like Sorcerers or Warmages.
Like many "normal" spellcasting classes, you can learn the ability to cast 9th level mysteries by 17th level. However, the requirement that you have to know two mysteries of a previous level before learning the next, means that to actually earn your first 9th level mystery, you need to really build towards it and not deviate from that goal by taking more than two paths at each Apprentice / Initiate / Master grouping.
- In essence: each path you take beyond the second in each group, will suspend your ability to reach 9th level spells by a whole class level.
- It also means you'll only ever know TWO 9th level mysteries, since by the 18th casting level you can get your second 9th level mystery by completing two Master paths, but it leaves you with only two more levels before 20th with which to pick up a new path (or two) which you will never complete.
Making Shadowcasters work
Because the class is self-contained within a single sourcebook, nearly all the options available to you are present IN that book, so there are very few combinations of multi-class options that work especially well outside of that.
That said, the help text says that Shadowcasters can qualify for prestige classes that only have a "Caster Level" requirement and do not specify Arcane/Divine, or require specific knowledge of a specific spell;
However, they do not actually benefit where class advancement specifies increasing Arcane/Divine spellcaster levels. The ONE exception given is that they can qualify (and increase) as part of either casting requirement of Mystic Theurges.
Therefore outside of the Tome of Magic Sourcebook prestige classes that fit with Shadowcaster are extremely hard to find, there are only a handful of working options:
- (note that virtually none of Complete Arcane/Mage/Divine prestige classes either qualify or actually increase shadowcasting level when they do qualify, multi-class Shadowcasters DO NOT increase in caster level the same way that Warlocks do)
Ruathar (RotW), Fortune's Friend, Magical Trickster & Uncanny Trickster (Complete Scoundrel) are all easy to qualify prestige classes that only requires knowing spells of a certain level and increases spellcasting from any class. They all have short level progression so you'd have to figure out what you want to do with them.
Non-Good Half Elves can take the Scar Enforcer in Races of Destiny also provides simple entry requirements and generic caster advancements, though it drops your Shadowcaster level by half. The same applies to the Ollam (Complete Adventurer) for Dwarves, but that requires you to be Lawful Good which is a bit unfluffy for Shadowcasters.
Stormsinger from Frostburn can be qualified by multiclassing a single level of Bard and taking some points in Perform (Sing). Once enterered you continue with a full shadowcasting progression (missing out only the single level). Though the class features are heavily focused on Bardic Music so may not necessarily fit with most builds.
- Interestingly enough, the Rimefire Witch and Frost Mage from the same book also work. Though the prior requires divine spellcasting, and the latter requires arcane spellcasting (both at level 1) they both increase spells in any spellcasting class, not just the one needed to qualify.
Paragnostic Apostle from Complete Champion works quite well, since the class abilities are broad enough that they apply to everything that you do, and you learn something to enhance your magic at each level and you gain full caster level progression. This is definitely a good option for Shadowcasters looking to enhance what their Mysteries can already do.
Shadowcasters can also take the Earth Dreamer class from Races of Stone, which is quite easily qualified for and provides a bunch of extra spell-like or supernatural abilities that do not interfere with your core casting ability at all.
Despite the name, Divine Oracle from Complete Divine specifies the need for spellcasting abilities, but not whether they need to be arcane or divine; accordingly, Shadowcasters can qualify so long as they can find a way to get their Knowledge (Religion) skill up cross-class and be able to cast two divination spells, which is easy to do. (This isn't even an exploit; there's a sidebar explaining that the designers wanted non-divine casters to be able to qualify.) It expands spell lists (but not spells/mysteries "known") with some useful divination spells, grants immunity to surprise and an evasion-equivalent that works even whilst you're wearing armour, so it's potentially a good option.