Robin Hood is the initial Persona of Goro Akechi in Persona 5/Royal. If you purchase the Royal Persoan Set 1 DLC in Persona 3 Reload, then you can equip Robin Hood to the protagonist. He's a Persona of the Justice Arcana in Persona 3 Reload, meaning you can have him with you when spending time with the Justice Social Link. Otherwise, Robin Hood has average stats and a good Skillset that makes him versatile in battle. However, you'll want to be wary of his Affinity Weakness to Dark.