Pathfinder 2 Unified Theory Feat
You can find Feat Rules here.
Unified TheoryFeat 15
Prerequisites legendary in Arcana
You’ve started to make a meaningful connection about the common underpinnings of the four traditions of magic and magical essences, allowing you to understand them all through an arcane lens. Whenever you use an action or a skill feat that requires a Nature, Occultism, or Religion check, depending on the magic tradition, you can use Arcana instead. If you would normally take a penalty or have a higher DC for using Arcana on other magic (such as when using Identify Magic), you no longer do so.
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Additional Lore | Adopted Ancestry | Alchemical Crafting | Ancestral Paragon | Arcane Sense | Armor Proficiency | Assurance | Automatic Knowledge | Bargain Hunter | Battle Cry | Battle Medicine | Bizarre Magic | Bonded Animal | Breath Control | Canny Acumen | Cat Fall | Charming Liar | Cloud Jump | Combat Climber | Confabulator | Connections | Continual Recovery | Courtly Graces | Craft Anything | Diehard | Divine Guidance | Dubious Knowledge | Expeditious Search | Experienced Professional | Experienced Smuggler | Experienced Tracker | Fascinating Performance | Fast Recovery | Feather Step | Fleet | Foil Senses | Forager | Glad-Hand | Group Coercion | Group Impression | Hefty Hauler | Hobnobber | Impeccable Crafting | Impressive Performance | Incredible Initiative | Incredible Investiture | Intimidating Glare | Intimidating Prowess | Inventor | Kip Up | Lasting Coercion | Legendary Codebreaker | Legendary Linguist | Legendary Medic | Legendary Negotiation | Legendary Performer | Legendary Professional | Legendary Sneak | Legendary Survivalist | Legendary Thief | Lengthy Diversion | Lie to Me | Magical Crafting | Magical Shorthand | Multilingual | Natural Medicine | Nimble Crawl | Oddity Identification | Pickpocket | Planar Survival | Powerful Leap | Quick Climb | Quick Coercion | Quick Disguise | Quick Identification | Quick Jump | Quick Recognition | Quick Repair | Quick Squeeze | Quick Swim | Quick Unlock | Quiet Allies | Rapid Mantel | Read Lips | Recognize Spell | Ride | Robust Recovery | Scare to Death | Shameless Request | Shield Block | Sign Language | Skill Training | Slippery Secrets | Snare Crafting | Specialty Crafting | Steady Balance | Streetwise | Student of the Canon | Subtle Theft | Survey Wildlife | Swift Sneak | Terrain Expertise | Terrain Stalker | Terrified Retreat | Titan Wrestler | Toughness | Train Animal | Trick Magic Item | Underwater Marauder | Unified Theory | Unmistakable Lore | Untrained Improvisation | Virtuosic Performer | Wall Jump | Ward Medic | Wary Disarmament | Weapon Proficiency