School of Arcanum

Some wizards focus on specific schools of magic, devoting themselves to divination or conjuration, while others take a more broad approach, hoping to immerse themselves in all sorts of magic. The School of Arcanum, however, has a specific interest in the nature of magic itself. While members learn and cast spells like most other wizards, they also devote themselves to understanding the hidden nature of each one, seeking to uncover the mechanics that govern the weave of magic itself.
Many wizards see this as a noble aspiration, but disapprove of the methods that members of this school undertake. In the pursuit of their goal, the School of Arcanum helps itself to the hidden techniques of any race or creed. Sneaking into the restricted sections of libraries, uncovering lost spells from long forgotten tombs, and the most cardinal sin of all wizards, stealing the spellbook of another. Anything is fair game in the pursuit of the secrets of the arcane.

Clandestine Education

2nd-level School of Arcanum feature

You gain proficiency with light armor, thieves' tools, as well as the Stealth and Sleight of Hand skills.

Concealed Spellbook

2nd-level School of Arcanum feature

Members of the School of Secrets know that a spellbook is the most precious, and the most useful, item that a wizard has. As a result, they take measures to protect their own.
Your spellbook cannot be opened by anyone other than you, as you cover it in arcane wards. These wards are immune to dispel magic, but can be broken with a successful Intelligence (Arcana) or Strength (Athletics) check against your spell save DC. You are made aware of this when it happens, and you can use a reaction to expend one spell slot, dealing force damage to whoever opened it as they activate a trap hidden within the wards. The damage is 2d6 + your proficiency bonus, plus an additional 1d6 for each spell level higher than 1st.
You can also summon your spellbook back to you if it is not on your person for whatever reason. So long as it is within range, you can use an action and expend one spell slot to teleport your spellbook into your hands. If you attempt to summon it and it is out of range, the spell slot is not expended, but you cannot attempt to summon it again until you have completed a long rest. The range of this ability is based on the level of the spell slot you attempt to expend, as shown on the table below.

Renaissance Magician

6th-level School of Arcanum feature

You learn a cantrip and one spell of your choice from any class. The spell must be of a level you can cast, as shown on the Wizard table, and the cantrip doesn't count against the number of wizard cantrips you know. At 10th level and 14th level, you can pick one additional spell and add it to your spellbook. When you gain a level in this class, you can swap out one of the spells you know for another.

Arcane Espionage

10th-level School of Arcanum feature

You add the following spells to your spellbook if you don’t have them already, and they are always prepared, but they don't count against the number of spells you can prepare. In addition, you learn how to cast them in enhanced ways in order to better suit your needs.

• When you cast the disguise self spell, the first time a creature interacts with the illusion, it becomes tangible for six seconds.
• When you cast the knock spell, it doesn't create any noise.
• When you cast the passwall spell, you can make the passage up to 50 feet deep, with both ends being concealed by an illusion which makes it appear that there is no breach.

Renaissance Magician

10th-level School of Arcanum feature

When you reach 10th level in this class, you add one additional spell of your choice from any class to your spellbook.

Renaissance Magician

14th-level School of Arcanum feature

When you reach 14th level in this class, you add one additional spell of your choice from any class to your spellbook.

Protean Spellcaster

14th-level School of Arcanum feature

You gain the ability to interrupt someone else's casting and use the spell for yourself. When you successfully interrupt a spell being cast through the use of counterspell, you can temporarily add it to your spellbook, so long as it is at least 1st level and of a level you can cast, though it doesn't need to be a wizard spell. The spell stays in your spellbook until either you use this feature to capture another spell, or until you scribe a spell scroll of the borrowed spell. If it is on your spell list, you can copy it into your spellbook permanently by copying it back after you create a spell scroll.