Here are the similarities:
- Disputed paternity: Yorkists alleged for a long time that the combination of Henry VI’s notorious piety on matters of the flesh and his repeated mental breakdowns meant that Marguerite d’Anjou had slept with one of her court favorites (either the Duke of Somerset or the Earl of Ormonde) to conceive an heir after eight years with no issue.
- Violent tendencies: Edward was more than a bit enthusiastic about war; in addition to talking about war, he also “talks of nothing but of cutting off heads,” and “delighted in attacking and assaulting the young companions attending him,” although it’s a bit ambiguous whether that was referring to military training. What’s not ambiguous is that, after the Second Battle of St. Albans, Edward ordered that the two Yorkist knights who had been guarding his father be decapitated, despite the fact that they had voluntarily stayed on the field to protect his father and had honorably surrendered. He was also reportedly a big fan of the decapitation and spiking of the Duke of York, his son the Earl of Rutland, and the Earl of Salisbury after Wakefield, so the beheading thing was a bit of a common thread.
- Engaged to the enemy: Edward of Lancaster was married to Anne Neville, the younger daughter of the Earl of Warwick, who had been one of the chief supporters of the Yorkist cause and the opposing general at the Second Battle of Albans, for example.
- Similar rival: Just as Joffrey was enraged at the victories of Robb Stark the Young Wolf, Edward of Lancaster’s main opponent was the young Edward IV, who similar to Robb Stark was always victorious when he was commanding but who was undone when he broke his betrothal and made an impulsive marriage.