Shepard chose to destroy Sovereign. The Council then declared war on the SA for that betrayal. The Humans tried to fight but it was a losing battle. Subjugation leading to extinction was not acceptable for making the hard military decision so the Humans chose another path and made a deal with the Reapers. The galaxy and the Cycle would never be the same. AU Terrans have a big stick

Humanity, left to its own devices for centuries, comes into contact with the Citadel Council. A misunderstanding leads to hostile first contact, and the UNSC is drawn into war with the Council shortly after the Insurrection's height. The Council finds itself face-to-face with a species that has broken the shackles of Mass Effect Technology. The Era of Humanity has only just begun.

When two worlds with predefined mindsets, knowledge, and ideals have to throw all of that out the window after contacting a new player. Humanity. (Babylon 5/Mass Effect AU crossover with a Star Trek-based Humanity and Stargate-based Precursors)

A small change in the past by SG-1 may have unexpected side effects for the rest of the galaxy.

The scrolls tell that 13 tribes left the birthplace of humanity on Kobol, 12 went one way and the other Earth went another only to lose all contact with their cousins. It is written that one day they would reunite but when they Earth meets their cousins it is not what they expected and it would cost both sides in blood. (Stargate SG1/Battlestar Galactica)

A John-clones falls into the same solar system as Middle Earth. Includes Medicine, Finance, Physics, Biology, and Violence. Also, what happens if you introduce the concept of 'loans' and 'investment' to a dragon. No slash- seriously, what's up with all the bagginsheild fanfiction? Just no. Updating quickly because my muse is rabid.