In a podcast they also linked 3 campaigns in the same world but in different timelines. The old chars are either dead or some kind of demigod or even gods so they are still part of the world and it's nice for the players to have a kind of monument what they achieved with their old chars.
They are also using a very cool method when telling an very old and important story - they are playing it with different characters. A god shows them what happened in the past and they have to play it and that is something that I definitely want to implement into my games because it's awesome especially if they already know something about what happened.
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My only caution with that is that you want to make sure that any new players don't feel left out.
With that said, allowing previous events to impact the present reinforces the benefits of roleplaying instead of just staying home and playing video games.