Regal is the only child of Shrewd and Desire. His mother believes that he is more royal and therefore more deserving of the throne because of her own royal bloodlines. However, as the third son, Regal is considered unlikely to inherit, and hence is not groomed for ascension as Chivalry and Verity are. This includes tutelage in the Skill, in which Regal is untrained and untalented.
Regal's outlook is heavily influenced by his mother. He inherits most of Desire's beliefs, including that of his own fitness to rule, which strains his relationships with his half-brothers. Regal favors the inland Duchies over those on the coast, as Desire hails from Farrow. He also develops a fondness for various drugs and drink, which leads to Desire's death and his own increasing instability.
When Chivalry abdicates the throne, Regal becomes second in line, much to his mother's pleasure. Fitz's existence, however, is a potential snag in the line of succession, unacknowledged though he is. Regal is aware of this fact and dislikes Fitz from the moment he is brought to Buckkeep.
Regal is charged with selecting a bride for Verity. He eventually settles on Kettricken, as the link to the Mountain Kingdom will enrich the Six Duchies. As Verity must remain in Buckkeep to continue Skill-fogging the Red Ship Raiders, Regal agrees to give Verity's vows in his stead.
In Jhaampe, Regal becomes displeased when Fitz does not assassinate Rurisk as quickly as he had hoped. He summons Fitz and orders him to report, horrifying Fitz with how frankly he discusses Fitz's work. Fitz relays the conversation he had with Rurisk and Kettricken, in which they divulged that they knew of his task and would not hesitate to expose him if Rurisk were to die now. Regal is nonplussed by this and orders Fitz to carry out the assassination anyway by placing a poison powder into Rurisk's wine.
Fitz divulges this plan to Rurisk, placing the poison in his glass and then putting it aside while they drink the rest of the wine. However, Regal evidently did not trust Fitz to follow his orders, and had the wine poisoned beforehand. Rurisk dies, and Fitz is captured; Regal expects him to die as well. Regal communicates to Galen that things have not gone as planned in Jhaampe, but they agree to hold course for the wedding.
The next morning, Regal has Burrich bring Fitz to him in the steam baths. An unseen soldier clubs Burrich, knocking him out, though Regal believes him dead. Regal pushes the weakened Fitz into the deeper bath and leaves him to drown, assuming that his death will be recognized as an accident.
He killed his own father and usurped the throne. He stripped the Coastal Duchies of their riches and moved in land to the palace of his mother's people. Using the coterie built by his half-brother Galen to track and kill Queen Kettricken and his nephews. By this point he had developed a taste for cruelty which he inflicted on animals, Forged and his own citizens.
His coterie is defeated and FitzChivalry Skill burns loyalty to the Queen and her son Prince Dutiful whom he serves slavishly. He meets an untimely death, murdered by a large rodent. It is suggested that the rodent is either Chade Fallstar's pet or the wit-bonded Ferret whose master died saving Fitz.