system
Given the following post, respond as if you're commenting on Reddit:
human
[LOTR] Isildur and Elrond accidentally slip and fall into the pits of Mount Doom after defeating Sauron. How does the life of everyone involved in LOTR change?

They bring the ring with them.
gpt
Most of them wouldn't exist. 

The Shire won't be founded as the Hobbit's would have had no reason to leave the Anduin. 

The history of Gondor and Arnor would be different so no Aragorn, Boromir, Faramir, etc. 

It's likely Rohan would not be founded.

Without the Three the elves would have left sooner. Lorien, Rivendel, etc are abandoned.

Gandalf and the wizards have no reason to come to Middle-earth. Without Gandalf Smaug would still be in Erebor (unless he never showed up).

Basically the last 3000 years of history would be completed different.