Helgram is the largest House in the Courts in terms of its population, nearly half again as large as the next-closest, House Jesby. Helgram has produced its fair share of legendary warriors, mages, priests, scholars and politicians, but is not really known for these things--it is known for being very, very large, and for having innumerable tangled ancient bloodlines of great nobility and renown.
What keeps Helgram from being more dominant than it is is the fact that its members spend as much or more time plotting against each other as they do against rival Houses. Helgram members betray, deceive and murder their closest relations with a frequency, viciousness and glee that makes the other Houses disapprove of them. Despite this, the House enjoys at least polite relations and alliances with nearly everyone, simply because their sheer size makes others fear to antagonize them too much.
Lord Nuaeol is the current head of House Helgram, the younger brother of the deceased Lord Ingel (notable as the father of Dara of Sawall), who died in the Patternfall War. He spends most of his time trying to make sure that various relatives (brothers, sisters, cousins, nieces, nephews and otherwise) don't wrest control of the House away from his faction. He somehow found the time in this to produce twin daughters, but no one is really sure how.
Lucinda and Mindara
"...he held up a card in either hand, and on the left-hand one was a silver-eyed girl with pale blonde hair, scowling and wearing blue, and on the right-hand one was her twin, smirking and wearing red..."
Lucinda wears red, Mindara wears blue. Don't ever confuse them, as they hate each other passionately, and have a reputation for doing extremely nasty things to those who mix them up.
Lucinda is a loner. Mindara is constantly surrounded by a flock of followers, suitors and sycophants. Lucinda is better with the Logrus than Mindara, but Mindara is a better sorceress. Lucinda is generally considered to be a fractionally nicer person than Mindara. This is not saying much.
Again, don't confuse them with each other.
Lucinda was sent to Amber as part of the diplomatic mission, and helped Arawn of Sawall save Queen Vialle's life at the Dinner From Hell. She recently went out into Shadow with Eorann, Theresa and Llewellyn.