To play a caster well you need to be able to customise your spell book for the opponents you’ll face. To do this you use metamagic feats. These feats allow you to take spells at different levels other than their native level with added effects, and so allow you greater flexibility to match spells to opposing resistances and saving throws. There are four metamagic feats that allow you to customise a spellbook: Extend Spell, Silent Spell, Empower Spell, and Maximise Spell. Empower Spell adds +50% to variable damage effects. 2D6 becomes 2D6 multiplied by 1.5.