Straight: Wilhelm has taken fledgling hero Bob under his wing and been teaching him the arts of swordfighting and heroism. Unfortunately, they are attacked by the Black KnightButcher, and Wilhelm is slain protecting Bob. His death drives Bob to fight the Black Knight's forces and ultimately save the world.
Exaggerated: After losing Wilhelm, Bob gathers several allies: Alice, Marcy, Pike, Cassandra, and Leon. As it turns out, all of them lost their mentors to the Black Knight.
Downplayed: After a fight with the black night, Wilhelm decided to take on a pupil to pass his skills onto before an injury he had gotten takes his life. On the night of death, Bob swears to use the skills he had gained to prevent any more deaths.
Justified: The Black Knight forces Wilhelm to sacrifice himself to allow Bob to defeat the Black Knight in the long run.
Inverted: Dead Sidekick. Wilhelm loses Bob to the Black Knight and vows revenge.
Wilhelm duels the Black Knight in what looks to be his heroic last stand... and wins, returning to Bob in triumph.
Wilhelm died long ago and is a ghost when Bob meets him.
Double Subverted: Wilhelm defeats the Black Knight, turns to Bob, smiles... and the Black Knight runs him through from behind.
Parodied: Wilhelm finds that his Big Book of Hero Mentoring instructs him to die at some point.
Zig Zagged: Wilhelm fights the Black Knight and wins, only to die shortly after from exertion. However, he later comes Back from the Dead... only to be killed off again by Bob's latest nemesis.
Averted: Wilhelm sends Bob out to stop the Black Knight, since he's getting too old for the heroing business. He does not get killed off.
Enforced: The execs fear that Wilhelm is overshadowing their Idiot Hero, so they have him killed off.
Lampshaded: Wilhelm's last words to Bob express that he never had much of a chance anyway.
The Black Knight deliberately seeks out experienced warriors who have just taken on trainees, in order to scar those rookies for life and either intimidate them into giving up or provoke them into seeking him out, providing a potential challenge in the future.
Alternatively, Wilhelm lets himself die at the Black Knight's blade with the intention of motivating Bob to fight the Black Knight's forces
Defied: "You know what, this Black Knight guy's bad news, and I ain't getting myself killed just 'cuz you happened to piss him off somehow. I'm moving to Aruba until this whole thing blows over. Good luck!"
Conversed: "Look, Bob's wise old mentor is about to fight the Black Knight. Betcha he bites it."
Part or all of Wilhelm's character arc is him wondering whether or not he should or is going to die.
Losing Wilhelm does not make Bob stronger — if anything, it weakens his resolve, giving him a crippling fear of the Black Knight Butcher. After all, Wilhelm was the strongest man he knew; if he lost to the Butcher, what chance does Bob have?
Reconstructed: After seeing the Black Knight slay his mentor, Bob is gripped by fear, but gradually works through his terror and becomes a stronger person, eventually capable of facing the Black Knight and avenging his master.
Played For Laughs: The Black Knight knocks Wilhelm down. Cue Big "NO!" from Bob and his tearfully swearing revenge, despite Wilhelm's protests that he's perfectly fine and just needs a helping hand up... then Bob runs off, leaving Wilhelm laying there. "Hello...?"
Played For Drama: Wilhelm took the orphaned Bob in and has become a surrogate father figure for the young man, raising him to the best of his ability. Unfortunately, the Black Knight has heard of Wilhelm's reputation and decides to kill him just to "prove who's stronger". Bob tries to step in, but is thrown aside and watches helplessly as Wilhelm is struck down.