Is It Possible To Use A Weapon To Perform Spells?

In D&D 5E, spells have a somatic component, which requires hand movements. The rules state that one hand is needed to cast these spells, even when wielding a two-handed weapon. When a hostile creature’s movement provokes an opportunity attack from you, you can use your reaction to cast a spell at the creature.

A spellcaster must have a hand free to access a spell’s material components or hold a spellcasting focus, but it can be the same hand that they use to perform. When a spellcaster casts a spell using a slot of a higher level than the spell, the spell takes on the higher level for that casting. For example, if a Wizard casts Magic, they can trace the somatic component of a spell using a weapon or object of comparable size in one or both hands.

Artificers can also cast spells without a free hand potentially. Any infused item counts as a focus for their spells, so they can cast with a shield, weapon, armor, boots, or their bag. Two-handed weapons only require two hands on them.

War Caster allows you to use the somatic part of your spell even if you are holding weapons and shield. The general rule remains that you only need one free hand to cast a spell, and only if it has a somatic component. In D&D 5E, to cast spells, you need to have a free hand until you take a warcaster feat. There are customization/build options available for this purpose.

In summary, spells with somatic components require hand movements and can be cast with one hand free. War Caster allows for the use of the somatic component of a spell even when holding weapons or a shield.