Firbolgs have some innate spellcasting from their Firbolg Magic ability. They will cast Detect Magic and a modified form of Disguise Self that lets them to look 3ft shorter to Mix in with humanoid creatures like elves. They may be summoned from the Lord of Blades, demanding they go see https://triton-dnd93580.wizzardsblog.com/28109027/5-tips-about-goliath-dnd-you-can-use-today