Spoilers: I'm going to stick to Basics for a while, even though they contain spoilers...
AKA: Gwen, Lord Walde, Chancellor Lord Walde
Age: ~150 in year 0
Looks: tall, charcoal grey hair, grey eyes.
Character: Dour and repressed. Hard-working, dutiful, hides his sentimentality.
Special skills: Administrator. Knitting. Swordsmanship.
Family: As per the anime.
In PW, Gwendal married Annissina von Khrennikov, terrified that she would marry Manfred von Bielenfeld, Wolfram's father, if Gwendal didn't beat him to it. By Epilogue, they have their first child together, Grendel. Annissina still terrorizes Gwendal, especially the way she whips out an ample breast to feed the baby in public.
As Chancellor, and leader of the Federalist coalition in the Eleven Aristocrats, Gwendal seems to be losing ground to Aldrich von Bielenfeld's Autonomist coalition lately. Conrad is a recent defector (TwT) and everyone expects Sylvain Lord Donaghie to fall into Aldrich's camp, too. He's losing political clout to little brother Wolfram, and military authority to the outspoken Gregor von Dienst, and Yuuri is growing into his kingship as well. So Gwendal's authority is on the wane.
In TwT we learn a bit about Gwendal's father, the great General Lord Walde who masterminded Shin Makoku's military through the Great Troll and Goblin War. The General was himself part goblin, kept in a tower during the war, to protect him from entrollment. Much later, on his deathbed, he still grieved over having fought 'his own' people in that conflict. Since the Great War ended 80 years before Gwendal was born, the General was older than Gwendal's mother Cecilie von Spitzweg. Apparently, the couple 'brought out the best in each other' for whatever time they had together, and the General died in bed, wife and son near at hand.
- A Fully Justified Kick - at Yuuram's wedding (by bananam00n and Jinjyaa)