# War Caster *Source: Player's Handbook (2024) p. 209* **Prerequisite**: 4th; Spellcasting or Pact Magic feature You gain the following benefits. ## Concentration You have Advantage on Constitution saving throws that you make to maintain [Concentration](conditions.md#Concentration). ## Reactive Spell When a creature provokes an [Opportunity Attack](actions.md#Opportunity%20Attack) from you by leaving your reach, you can take a Reaction to cast a spell at the creature rather than making an [Opportunity Attack](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 in one or both hands.