So while the other houses have interbreed to reduce the number of Shanir, the Ardeth deliberately kept the old tradition to produce them. Their Highborn bloodline is kept purely Ardeth, with no interbreeding with other houses. They are very proud of their pure bloodlines.
They've traditionally been allies of the Knorth, perhaps because both houses resisted interbreeding with other houses. In recent times, Torisen's relationship with Adric has both strengthened and stressed their bond.
↑To Ride a Rathorn, "Chapter VII: In the Bear's Den", I — "each house fitting into the pattern, […] subtle Ardeth"
↑To Ride a Rathorn, "Chapter I: An Unfortunate Arrival", II — "The Ardeth were an arrogant lot, proud of their subtle lord"
↑Seeker's Mask, "Part II: Gothregor", III — "She remembered Ganth raving about it in the Haunted Lands keep on those nights when no one slept. […] the scheming Ardeth,"
↑Dark of the Moon, "Appendix II: The Master's Generation" — "cross-breeding between houses has become more and more the rule. Now all the lords of the High Council have mixed blood except Torisen and Adric. The Ardeth have always had a special interest in the Shanir."
↑Honor's Paradox, "Chapter VII: The Day of Misrule", II — " 'Should I give the world another bastard? The Ardeth are jealous of their oh-so-pure blood, more than any house except yours. Timmon should have thought about that when he spent his precious seed on me.' "
↑"Songs of Waste and Wood", IV — " 'No doubt you are one of Adric’s bastards, eh? Perhaps of mixed or unclean lineage? That house is so proud of its pure bloodlines.' "
↑Dark of the Moon, "Chapter 6: The High Council" — "On the western wall, catching the last of the day's light, was his own rathorn crest, flanked by Ardeth's full moon and Jaran's stricken tree. They were the two oldest supporters of his house, in more ways than one."