House Targaryen is a noble house of Valyrian descent.
Their sigil is a three headed red dragon on a field of black. The three heads represent Aegon the Conqueror and his sisters, Rhaenys and Visenya. Their words are "Fire and Blood"
Daenerys Targaryen is the last confirmed member of the ancient Targaryen Dynasty.
Her father King Aerys was killed in Robert's rebellion, but Daenerys' mother and brother, Viserys, escaped. She was born a few months later, but her mother died in childbirth and Daenerys and Viserys were smuggled into exile.
Ser Jorah Mormont is an exiled Northern lord in the service of Daenerys Targaryen.
Initially he joins with Daenerys to spy on her for Varys, but he grows to admire and respect her, and becomes genuinely loyal to her.