Is there any way to replicate the concept of a "Blue Mage"?

[Malik Gyan Daumantas]

For context a blue mage is a type of spell caster with the ability to copy spells from other classes and are able to use spells they realistically have no business being able to use.

[Makarion]

Illusionist? As long as everyone else believes it... A heavens oracle with Awesome Display can go a long way, I think.

[Claxon]

Not in the real mechanical way you're referring. In part because a lot of spell lists are are shared between classes and because there are so many ways to get spells that aren't on your spell list.

I just don't think this is a concept supported within Pathfinder.

I think the closest you might be able to get is Razmiran Priest/Flase priest sorcerer archetype that lets you use divine scrolls + your spell slots to cast divine spells (without expending your scroll). Having the wizard/sorcerer/cleric spell list gets you a pretty diverse set of spells.

[Dragonchess Player]

Probably the closest in concept would be one of: Magaambyan initiate arcanist; ancient lorekeeper (elf only), elementalist, etc. oracle; or a shaman (maybe true silvered throne?) with the Lore spirit using Arcane Enlightenment.

Other archetypes exist that add spells to the class spell list.

Magus can add wizard spells with Spell Blending arcana.

Multiclassed sandman bard/witch can cast spells that are "normally" found on different lists (as the bard and witch spell lists are sort of hybrid arcane/divine already) and can also "steal" spells.

A samasaran with the Mystic Past Life alternate racial trait can add spells from another list.

There are also feats that allow a character to add spells that would not normally be on their list: Fey Spell Lore, Fey Spell Versatility, and Unsanctioned Knowledge (there might be others that I don't recall).

Otherwise, a character could always research versions of existing spells on other class lists for their class list. See Designing Spells; usually, a version of a spell from a different list should be one spell level higher.

[Makarion]

It occurs to me that we may be asking the wrong question. What we *should* be asking is how to make the Blue Raja. One of these days, that Fork specialisation is going to pay off, I tell you!

[zza ni]

No archtypes or special races needed.
I always considered the skald's "spell kenning" ability to be something akin to blue magic.

Spell Kenning:

Spell Kenning (Su): At 5th level, a skald is learned in the magic of other spellcasters, and can use his own magic to duplicate those classes’ spells. Once per day, a skald can cast any spell on the bard, cleric, or sorcerer/wizard spell list as if it were one of his skald spells known, expending a skald spell slot of the same spell level to cast the desired spell. Casting a spell with spell kenning always has a minimum casting time of 1 full round, regardless of the casting time of the spell.

At 11th level, a skald can use this ability twice per day. At 17th level, he can use this ability three times per day.

[Malik Gyan Daumantas]

zza ni wrote:

No archtypes or special races needed.

I always considered the skald's "spell kenning" ability to be something akin to blue magic.

** spoiler omitted **

Yeah and i also realized that shadow magic can very easily fall into the blue magic catagory as well.

[Temperans]

Stylish Spell (forget exact name) also helps. Just literally change the manifestation of whatever spell to look like anything and start from where ever you want.

[Java Man]

The spell sage wizard with one level Loremaster to grab the Secret of Magical Discipline feat as many times as possible.

[Umbral_Magmus]

The best archetype to do this is the Occultist Psychodermist.

[UnArcaneElection]

Also consider Spell Sage Wizard, and then invest in Use Magic Device. You start out with normal 9/9 casting from the Sorcerer/Wizard list but with no Arcane Bond or Arcane School. But in exchange for losing Arcane Bond, you get Focused Spells, which lets you boost your Caster Level (initially once per day, but you gradually get more uses). And in exchange for losing Arcane School, you get Spell Study, which lets you poach a spell from the Bard, Cleric/Oracle, or Druid spell lists, again with uses per day starting out at 1, but gradually increasing. Now, the latter ability is slow, so you wouldn't want to use it in combat. But you still have Scribe Scroll, so you could make Scrolls of spells you poach, and then resort to these and your Use Magic Device skill to fire off these spells in combat if needed. In some cases you actually want to cast the spell yourself, because if you need to make an opposed Caster Level Check (like for instance, for bad status removal), you will want to use Focused Spells together with Spell Study to give yourself the best shot at success. Naturally, if you acquire other Item Creation feats, you could also use Spell Study to supply the spell requirements for those as well. Not sure about using Focused Spells to boost the item caster level, but I think it should work (although if you do that with a Spell Completion/Trigger item like a consumable, that is going to make it more expensive).