Guild Sister

The Guild Sister is the ultimate flexible spellcaster. They utilize the Guild Magic feat to "learn" a new set of spells when they need them, rather than spending feats to learn new spells. The trade off is higher PP usage and requiring additional Guild Magic feats to take full advantage of their spellcasting abilities.
This class combines well with many classes, and oddly enough can be tweaked to make a decent fighter by using the Grant Ability spell to gain combat feats rather than spells. The Crossbow or Firearms Fighter is an easy class to use with this one, due to INT being an important Stat for both.
Primary Stat- INT
Focused Skills- Guild Magic, Summon Magic, and Alteration Magic
Feats
Smug Intellectual
Guild Magic
Spell Modification
Quick Cast
Quicker Cast
Guild Sister
Increase Pool (take multiple times)
Guild Mage
Combine Spell
Technical Spell Modification
Metamagic Specialization
Metamagic Mastery
Rapid Cast
Greater Combine Spell
Guildmistress
Spell Focus (take multiple times)