Dragon Ancestory Sorcerer

[JumboWheat01]

I have a simple question about sorcerers who get their magic through their dragon ancestor.

What happens to their magic if you happen to kill said dragon? I mean, it's bound to happen. A sorcerer most likely isn't the same alignment of their dragon ancestor, and killing dragons is kind of one of those adventurer things. Will they keep their magic, as it's actually a part of them, and they can continue to pass it on, or will it just go all fizzled and that's that. Or will it be something of a combination of the two, they keep their sorcerous power, but they're the last of the bloodline?

[zylodrizzt]

Its a bloodline. Its in their blood. Its like breathing. Nothing short of killing the character will separate him from his power. Same goes for warlock or paladin. Just cause he broke the deal with a devil doesn't mean he just ceases to have power it just means he is going to have demonic hitmen on his tail. Paladin may or may not switch his oath most often to oathbreaker or back if even that but he doesn't cease to be a paladin. A ranger loses his beast companion doesn't just cease being a beast master ranger. A fighter who loses both arms doesn't just cease being a fighter. A barbarian who learns about being civilised doesnt cease to be a barbarian. My point is in this edition of dnd just like 4th isn't so restrictive.

[Addaran]

The sorcerers get their powers because the ancestor is a dragon, not from him.
It's more akin to being an half-elf then the cleric way of getting your powers.

The cleric's god die, the cleric loses his power until he finds another god.
The half-elf kill his elven parent, he doesn't become a human. (or kill human parent doesn't become elf)

[Stray]

As usual depends on setting and it's DM's call. If you want draconic bloodline sorcerers linked to the beating heart of their ancestor in your setting, go for it. Just consider that taking away character's class because of event player had no control over isn't very cool. So last of the bloodline might be better choice.
(in 4th edition a warlock could betray their patron without loosing class features or ability to continue leveling in this class, even thought warlock-patron relationship is more personal than sorcerer-ancestor. As far as I know 5th doesn't cover what happens when warlock patron gets destroyed)

In most cases though I would say it has no effect. It's the draconic blood in their veins (or DNA if you like some science in your fantasy) that powers sorcerers magic, not a lifelink to a specific dragon. Death of your great-grandparent won't take away your eye color, it's part of you.

And how much draconic bloodline involves literal dragon ancestors is also up to DM and setting. It could easily represent dragon cult blood rituals, being born close to dragon's lair or even side effects of slaying a dragon. As long as your character or their ancestor was involved in any way with dragons, you could spin it as source of draconic bloodline.