Arcane Spellcasting (Magus)

You study spells so you can combine them with your attacks or solve problems that strength of arms alone can't handle. You can cast arcane spells using the Cast A Spell activity, and you can supply material, somatic, and verbal components when casting spells.

Because you're a magus, you can draw replacement sigils with the tip of your weapon or your free hand for spells requiring material components, replacing them with somatic components instead of needing a material component pouch.

At 1st level, you can prepare one 1st-rank spell and five cantrips each morning from the spells in your spellbook. Prepared spells remain available to you until you cast them or until you prepare your spells again. The number of spells you can prepare is called your spell slots.

As you increase in level as a magus, your number of spell slots and the highest rank of spells you can cast from spell slots increase. Because you split your focus between physical training and magical scholarship, you have no more than two spell slots of your highest rank and, if you can cast 2nd-rank spells or higher, two spell slots of 1 rank lower than your highest spell rank. For anything that requires the ability to cast spells of a certain rank that's lower than the highest slots you have, you still qualify even if you no longer have spell slots at those ranks.

Some of your spells require you to attempt a spell attack roll to see how effective they are, or have your enemies roll against your spell DC (typically by attempting a saving throw). Your spell attack rolls and spell DCs use your Intelligence modifier.

Heightening Spells

When you get spell slots of 2nd rank and higher, you can fill those slots with stronger versions of lower-rank spells. This increases the spell's rank, heightening it to match the spell slot. Many spells have specific improvements when they're heightened to certain ranks.

Cantrips

A cantrip is a special type of spell that doesn't use spell slots. You can cast a cantrip at will, any number of times per day. A cantrip is always automatically heightened to half your level rounded up—this is usually equal to the highest rank of spell you can cast as a magus. For example, as a 1st-level magus, your cantrips are 1st-rank spells, and as a 5th-level magus, your cantrips are 3rd-rank spells.

Spellbook

Every arcane spell has a written version, usually recorded in a spellbook. You start with a spellbook worth 10 sp or less, which you receive for free and must study to prepare your spells each day. The spellbook contains your choice of eight arcane cantrips and four 1st-rank arcane spells. You choose these from the common spells on the arcane spell list or from other arcane spells you gain access to. Your spellbook's form and name are up to you. It might be anything from a sturdy book with a secure latch entitled Theses on the Stratagems of Supernatural Warfare to a tattered collection of training pamphlets with your name scrawled on the cover.

Each time you gain a level, you add two more arcane spells to your spellbook, of any rank of spell you can cast. You can also use the Arcana skill to add other spells that you find in your adventures. Though you lose some lower spell slots as you increase in level, you keep the spells in your spellbook and can prepare them in your higher-rank slots as normal.

If you have a spellbook from multiple sources (such as being a magus with the Wizard Dedication feat), you can use the same spellbook for all your spells.