The Order of the Iron Gauntlet is the oldest in the Kingdom. They are the order of the King’s Guardian Knights. Though they are Generals and Warriors of note, they act as the King’s bodyguards in battle and interesting situations.
This is a knightly order of the kingdom, which does not require its members to of noble line, just noble attitude. Each member must be knighted for duty to kingdom or be of knightly rank (or greater) by birth. The order was formed by the Queen of the Rose, Queen Isa, hence the name. The order’s primary duty is as The Queen’s Guard.
War of the Roses as a campaign plot. Two noble lines converge somehow, each line thinks it has the rightful claim to the throne. Deciding this long ago was handled by some divine intervention, requiring both houses to come together at some point. They aren't so willing to get together this time. Civil war, or a new king?