TV characters introduced on one show who die in another

[Chris Lang]

Recently, Law and Order: Special Victims Unit and Chicago PD did another big crossover event, in which the detectives of both precincts join forces to apprehend the serial killers Carl Rudnick and Gregory Yates. The latter killer, Gregory Yates, first appeared in a previous crossover event -- during which he killed a close friend of Chicago PD's lead female detective, Erin Lindsay. The finale of the crossover, 'The Song of Gregory Williams Yates', deals with Lindsay's final confrontation with her friend's killer.

But it's interesting to note that said friend was a recurring character introduced on Chicago PD, but was killed during the Law and Order SVU episode part of the previous crossover. And this got me to wondering: How many times in TV history has a character been introduced in one TV show, but been killed off in another show?

Offhand, the only other times I can remember this happening are on Star Trek: Deep Space 9, where several Klingon characters introduced in the original Star Trek series and on Star Trek: The Next Generation die in various later episodes of DS9.

So, can anyone else give some examples of characters who die on TV shows other than the shows they first appeared in?

(Needless to say, this whole thread will likely contain spoilers)

[Holt]

Sarek from Star Trek: The Original Series was killed off decades later in an episode of Star Trek: The Next Generation.

[dragonmp93]

Hawkman was introduced in a crossover of the Flash and Arrow, and died in Legends of Tomorrow.

[JediMindTrick]

Wesley Windam Pryce started on Buffy but died on Angel.

Cordelia Chase started on Buffy but died on Angel.

Those are the two major ones from Buffy who died on Angel, there are probably some minor ones as well.

[Professor Moriarty]

Joanie and Chachi where introduced on Happy Days then Joanie's actress's career died on Joanie Loves Chachi.

[Immortal Weapon]

Hawkman was introduced in a crossover of the Flash and Arrow, and died in Legends of Tomorrow.

Deadbolt was introduced in Arrow and later dies in an episode of the Flash.

[Loki]

Jose Chung was introduced in X-Files and died in Millennium.