Spoilers: I'm going to stick to Basics for a while, even though they contain spoilers...
AKA: Lord Bielenfeld (ruled age ~510 - 780)
Age: ~778 in year 0
Looks: 5'3", grey-blond hair, green eyes. Half wood nymph.
Character: Reserved, dark humor. Accustomed to authority.
Special skills: Best fire healer in Shin Makoku. Painter. Scholar.
Family: Friedrich is paterfamilias of the ruling branch of the von Bielenfeld family. (The branches split long ago - they're not closely related now.) In BoW and Axel, Friedrich rules Bielenfeld, and Wolfram is his agent at court - not much of a job since Friedrich had little use for Cecilie or Yuuri. In PW, Friedrich's son Aldrich ousts him in favor of Manfred, Wolfram's father, then takes over in WTB. After brief irritation, Friedrich was OK with this - he never wanted to rule Bielenfeld in the first place, and Aldrich had been doing most of the work for years.
Friedrich, the famed beauty Emeraude, and Garena were treeborn triplets, offspring of the wood nymph Tariel and Theophilus Lord Bielenfeld, when Theophilus was ~220. These three were the only half-nymphs - immortal tree spirits don't do babies. But Theophilus hoped that by combining the life maryoku of the wood nymphs with the new fire healer gift (Theophilus' grandfather Breufeld was the first), the gift would be greatly strengthened and stabilized. The sole remaining wood nymph Tariel was persuaded, in hopes of re-establishing his race. Those hopes were dashed, though Theophilus got one super-charged fire healer - Friedrich. The children stayed with Tariel for a time (decades), then Theophilus legitimated the demonlike Friedrich and Emeraude. The nymphlike Garena was left behind. Emeraude insisted the nymphs were just make-believe she and Friedrich used to play. She went on to marry first a ruling Lord Wincott, then Lord Spitzweg, giving a number of supercharged maryoku demons to both domains - Suzanna Julia von Wincott and Cecilie von Spitzweg were her great-granddaughter and grand-daughter respectively.
Friedrich didn't forget Tariel and Garena, and remained pissed off at Theophilus (The Moron), who didn't care - Friedrich was his third legitimate son, and he had offspring right and left, eager to strew the fire healing gift hither and yon. Friedrich concentrated on healing studies and ran off with a fellow healer, a plantation noble's daughter, by age ~70. He re-established contact with Tariel and Garena, and traveled extensively looking for rare maryoku races. The happy couple settled in at the Bielenfeld Institute, where Friedrich became chair of healing. They had just one child, Wolfgang, when Friedrich was ~330. Wolfgang was also something of a playboy, but married and had one son, Wolfred.
Friedrich served some time as a military healer, but refused promotion beyond sergeant. To honor his strictly non-aggressive parent Tariel, he's never killed. Which was wise anyway - Friedrich's fire healing gift can kill at a glance, and he'd frighten people if they understood the full extent of his powers. But he has no objection to other people killing - it's the natural order of things.
When Friedrich was ~510, Theophilus had a Bad Idea. He thought he'd found the majutsu key to Shinou's powers. He threw a party to demonstrate his genius. An alarmed Friedrich tried to talk him out of it, but instead got stuck babysitting infant Wolfred and Theophilus' two youngest daughters, Sophie and Phoebe (aged 15 and 10). They all died, including Friedrich's wife and son. Friedrich inherited Bielenfeld and the family plantations, and had 3 small children to raise.
When he was starting to get the hang of all these new responsibilities, the Great Troll and Goblin War broke out. The 25th Maou (Cecilie's predecessor) relied heavily on Friedrich, who had a potent secret advisor in Tariel. When the war ended in a draw, the Maou married the young Trond princess Alana von Trondheim to him, and charged Friedrich to bring Trondheim into the family of domains, and raise their child, Aldrich, in both cultures, to be the mediator for future troll-demon conflicts. (The Maou knew of Friedrich's secret nymph ancestry.)
Friedrich's flamingly gay, off-the wall grandson Wolfred was his heir and favorite of the six children he raised - only two of them mine. Wolfred's death in a Mizrati war at age ~135 was a cruel blow. The girls irritated him no end, especially the way they drove off Friedrich's young wife Alana, which complicated his relationship with Manfred, Wolfred's son, raised by jointly by Friedrich and Phoebe and cross-fostered with Sophie. Friedrich and his replacement heir Aldrich are also very close.
Like virtually all Tariel's 'male' descendants, Friedrich is bi. (Tariel is neither male nor female - he's a tree spirit.) Since Alana lived in Trondheim, he kept a quiet series of male and female mistresses in Castletown. After being ousted as ruling Lord, Friedrich tried taking back the chair of healing at the Institute, but was still rather preoccupied with family affairs, and after centuries on the stage of power, he'd simply outgrown the professor role. By GoT, he's living at Trond Hall with Alana, doing medical research with more political scope, advising the new Lord Erick, and expecting a baby girl.
Though Friedrich has aged his looks (deliberately), it's highly unclear whether he's old, for him. There's no yardstick. Theophilus was long-lived for a demon (he died still hearty at age ~730), and Tariel is immortal. Friedrich's twin Emeraude died by misadventure, still a gorgeous woman. His twin Garena still looks young, but he's nymphlike. The much-younger Alana caught on to this and pushed Friedrich to look younger (GoT). So... though nearly Ulrike's age, and despite attempts to retire, Friedrich's headed back into the prime of life.
(Also in Well of the Five Kings, but I haven't written a summary of that one.)
Friedrich's comic: Legitimated
For whatever reason, I thought up this story to tell when I wanted to try drawing a story. It's not done yet, but on the off chance anyone reads these pages... Please let me know if you care whether I finish it.
(I drew these out of order - there are a bunch missing between pages 2 and N)