The Raven Queen does not make mistakes. She will tell you this herself, unprompted, in a voice that implies the conversation is over. Dyolf Nala Yerffej is the evidence to the contrary.
Centuries are long, even for gods. The Raven Queen occasionally walks the material plane when mass death events demand personal attention. Souls backing up at the gate, necromancers hoarding what belongs to her. The usual divine bureaucracy. During one such visit, in the aftermath of a catastrophic magical surge in the Thundertree region, she took mortal form to process the sudden influx of souls. The rift between the Shadowfell and the material plane was fresh and raw. The dead were confused. The living were terrified. It was administrative chaos.
She encountered a bugbear chieftain named Jeffrey Alan Floyd. Loud, unkempt, possessed of a charisma entirely incompatible with his personal hygiene. He was trying to serenade her with a broken lute outside a burning tavern. What happened next is classified. Divine-level classified. The ravens were dismissed for the evening.
Nine months later, Jeffrey's clan found a child in the chieftain's tent. Massive, furry, already scowling. Surrounded by ravens that would not leave. The shamans identified him as "touched by something very powerful that doesn't want to talk about it."
The boy showed no aptitude for bugbear traditions: raiding, ambushing, organized brutality. He showed massive aptitude for making noise. His first word was reportedly "LOUDER." His second was "ENCORE." By twelve he'd acquired a lute from a traveling merchant (the merchant gave it willingly after the boy "asked" at full volume from three feet away) and taught himself to play by ear. When he played, dead things responded. Not undead. Not zombies. Spirits. Ghosts of musicians, warriors, and one very confused accountant who died mid-audit and never got closure.
The Raven Queen sent emissaries. They offered structure: formal training in divine arts, a position in her court. He asked if her court had a stage. They said no. He said no.
At sixteen he declared himself Dyolf Nala Yerffej, claiming the name was "ancient Celestial for 'he who shakes the pillars of heaven.'" It is not. It is his father's name, backwards. Jeffrey Alan Floyd. No one has corrected him. The last person who criticized his name spent three days hearing phantom war drums in their sleep.
He carries a skull as his Spiritual Focus. He says it belonged to "the greatest drummer who ever lived." It's a skull he found in a ditch. The spirit inhabiting it seems happy with the arrangement. He has a Samsung Galaxy phone from another dimension, acquired during a Spirit Session involving a ghost from a place called "New Jersey." It has no signal, no battery life that makes sense, and a front-facing camera he uses to document everything. The Raven Queen has examined the device. She does not understand it. This bothers her more than she lets on.
The Tour Vest is real leather, real studs, real patches. RAVEN QUEEN (his mother's sigil, worn ironically and sincerely at once). GYGAX (legendary planar bard whose music shaped reality). CRITICAL HIT (his favorite battle cry turned band name). One raven feather, tucked behind a patch, that moves on its own. That's the Cloak of Protection.