During the 31 years without a Highlord, after Ganth's exile, Adric was one of the forces that held the Kencyrath together, and got the Ardeth through it.
When Torisen came to the Riverland at 15, he confided in Adric. Adric protected him, sending him to join the Southern Host as an Ardeth, and assining Burr to him as his servant. Burr reported to Adric during this time, delivering him reports of Torisen.
With all his other sons dead, Adric put all his hope in Pereden, and was devastated when he was killed. After that, Adric put his hope in his grandson Timmon, Pereden's son. He also goes south, where he searches for Pereden's body, all in vain, for it was already burnt.
In his old age, Adric resorted to his drugs for strength. In Honor's Paradox, his mind starts to go, and at the Lordan's Presentation, he calls Torisen "Ganth" when he first sees him.
Like all lords and matriarchs, Adric is Shanir with the power to bind Kencyr to him. He can also form bonds with animals, and had a bond with Brithany, his Whinno-hir mare. He has the white hair of a classic Shanir, although he's now old enough that age would've whitened his hair anyways.
↑ 1.01.1Dark of the Moon, "Chapter 12: Night Pieces" — "hid the disagreeable smell of the hemlock, but didn't mask the juice's bitter taste. Still, he had developed a liking for the stuff during his career as a diplomat nearly a century ago, and it did help to calm him."
↑ 2.02.1Dark of the Moon, "Chapter 2: The Hell Hunt" — " 'Yes, I am indeed mind-bound to Brithany, my Whinno-hir. That and my hair seem to be my only Shanir traits except, of course, for the ability to bind men to me.' "
↑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."
↑Seeker's Mask, "Part VIII: Kithorn" — " 'During my years as a diplomat, I earned a singer's right to the Lawful Lie.' "
↑Dark of the Moon, "Chapter 6: The High Council" — " 'He is the child of my old age, my last son. All the others died in the White Hills, fighting for your father. Sometimes I wish I had died with them.' "
↑To Ride a Rathorn, "Chapter I: An Unfortunate Arrival", II — "The Ardeth were an arrogant lot, proud of their subtle lord who in his one hundred and fifty odd years had brought his house through so many disasters that even the scrollsmen of Mount Alban had lost count. The worst had been the thirty-one years of chaos after the White Hills when, without a highlord, the Kencyrath had nearly fallen apart."
↑Dark of the Moon, "Chapter 2: The Hell Hunt" — "At fifteen, […] escaping the nightmare of his father's keep, […] Ardeth's Riverland keep… 'Sir, I am Ganth Gray Lord's son.' 'If you stay here, boy, the other Highborn will kill you. Join the Southern Host under my name. They'll think you're some bastard son of mine I'm trying to get rid of, but never mind. Here's your commission, and a servant, Burr.' "
↑To Ride a Rathorn, "Chapter I: An Unfortunate Arrival", II — "Everyone knew that old Adric had a taste for the exotic drugs of the Poison Courts and had resorted to them for help before now, sometimes with unnerving results."
↑Honor's Paradox, "Chapter III: Pyres and the Pit", VI — " 'Mother fears, though, that Grandfather is going soft. He’s certainly old enough and with this obsession of his…' "