# War Caster *Source: Player's Handbook (2024) p. 209* **Prerequisite**: 4th; Spellcasting or Pact Magic feature You gain the following benefits. **Ability Score Increase.** Increase your Intelligence, Wisdom, or Charisma by 1, to a maximum of 20. **Concentration.** You have [Advantage](/Rules/Source/variant-rules/advantage-xphb.md) on Constitution saving throws that you make to maintain [Concentration](/Rules/Source/conditions.md#Concentration). **Reactive Spell.** When a creature provokes an [Opportunity Attack](/Rules/Source/actions.md#Opportunity%20Attack) from you by leaving your reach, you can take a [Reaction](/Rules/Source/variant-rules/reaction-xphb.md) to cast a spell at the creature rather than making an [Opportunity Attack](/Rules/Source/actions.md#Opportunity%20Attack). The spell must have a casting time of one action and must target only that creature. **Somatic Components.** You can perform the Somatic components of spells even when you have weapons or a [Shield](/Rules/Source/items/shield-xphb.md) in one or both hands.