Battle Caster

Prerequisite: Requires the ability to cast at least one spell of 1st-level or higher

You're comfortable casting, even in the chaos of battle.

You gain a 1d6 expertise die on concentration checks to maintain spells you have cast.
While wielding weapons and shields, you may cast spells with a seen component.
Instead of making an opportunity attack with a weapon, you may use your reaction to cast a spell with a casting time of 1 action. The spell must be one that only targets that creature.