Tome of Prowess (3.5e Sourcebook)/Arcana

Arcana
The Arcana skill represents dedicated study into the workings of arcane magic. While that study manifests itself most strongly as the ability to better understand and recognize arcane magics, those who study Arcana also learn the underpinnings of creatures created and maintained with those magics, constructs and the undead. Characters with substantial training in Arcana can even use arcane spell trigger and spell completion items containing spells not normally accessible within their class, as well as ignore attribute requirements on magical items.

Key Attribute: Intelligence

Creature Insight
While learning more about how arcane magic functions, you've also learned more about what makes some of the most common arcane creations and allies, constructs and the undead, "tick". Constructs are solid, lifeless creations animated by magic bound to their frames. The undead are the remains of once living creatures, animated to serve even in death or to grant a form of immortality. You know enough about the basic working of these creatures to recognize what abilities any individual member might have, even those you’ve never seen before.

Attempting to identify or glean information about a creature is an immediate action. The DC for this check is 16 + the creature’s CR. The creature does not have to be alive for you to try to gather information about it, though deceased creatures need to be identifiable and largely intact.

Special: The arcana skill only allows you to identify undead and constructs, and there are five other skills that provide similar knowledge for other creature types. If you possess ranks in the other creature identification skills and your GM does not specify which particular skill you need to roll (and they have no obligation to tell you), you may check against all skills as part of the same action. In that case roll 1d20 one time as the base and report your total check result (this d20 roll + your skill modifier) for each skill to your GM separately. Your GM is responsible for making sure that you get the most information from your individual check results.

Identify Magic
When you run across magic, it’s nice to know if it’s magic that will help you or flay you alive. The Arcana skill primarily deals with the esoteric magic of wizards, though it can be used to identify spells or effects from any source. This ability allows you to identify a spell as it is being cast, identify a standing magical effect, identify magical residue after an effect ends, etc. Additionally, it allows you to learn the spell stored within an arcane spell completion or spell trigger item. However, you must have detect magic or equivalent spell active, or else wield an etheliometer to learn anything with this ability.

The action required for this depends on which of these two methods you use, and is described in those methods. You gain information about the magical phenomena based on your check result.

Special: The arcane skill is specialized for arcane magic. It is less efficient at identifying divine or primal magic effects than the appropriate skills, and it is useless for identifying divine or primal spell completion or spell trigger items. If you possess ranks in the other magic skills and your GM does not specify which particular skill you need to roll (and they have no obligation to tell you), you may check against all skills as part of the same action. In that case roll 1d20 one time as the base and report your total check result (this d20 roll + your skill modifier) for each skill to your GM separately. Your GM is responsible for making sure that you get the most information from your individual check results.

Arcane Item Affinity
A little knowledge about obscure arcane magical theory goes a long way. With it you can attempt to use arcane spell trigger or spell completion items even if you lack the ability to normally use the spells within them. But your skill with the arcane doesn’t stop there. Arcane magic is based on tricking the world into doing what you wanted it to do all along, and some of those tricks work to coax magic items into working for you even when you lack the prerequisite attributes. If a magic item requires a certain ability score to function, you can try to ignore that requirement as well.

For continuous use items with an attribute prerequisite, this check requires a swift action. Otherwise, the action to use this ability is included in the activation action for the item (often the spell's casting time). The DC for this check is equal to the minimum required ability score or 14 + the item's caster level, whichever is higher. If you succeed on the check, the item functions normally for a period of time based on your check result. You may not attempt this check again during any period while it functions normally, and must wait for the item to stop responding to you before you may make an additional check. If you successfully emulate an ability score to activate the item, the item responds as if you had the minimum required ability score.

Note that this ability only activates items that are arcane in nature or that have an attribute prerequisite to their use. It only covers those portions of the activation. Items that have an attribute prerequisite but are not arcane, or that have additional non-attribute prerequisites, may not be covered by this ability. In this case, additional checks with other skills may be required.

Special: If your use of this ability triggers a cursed item, the cursed item becomes activated and functions normally for you until the curse is broken by a spell, class feature, or similar ability. This indefinite duration replaces the normal check based duration.