This is the achievement that is one of the most difficult on xbox live it needs its own page. Details of links can be seen below to take you to all the places for everything you will need to obtain this achievement.

Feel free to discuss the achievement below and ask the community any questions, im sure someone will help you with your question.

How to earn:

To earn this achievement, you need to rank up to level 100 and earn all 65 onyx medals in the game.
The medals are awarded for specific tasks that you can do in the game.

One thing to note before starting this guide: You DO NOT have to have been in the beta or be Level 100 in Gears 2 to unlock this achievement.

The Easy Part:

Ranking up to level 100.. this is the easy part because you will automatically get this on route to your 65 ONYX Medals.

• One way to do this is to simply leave your console on overnight whilst in a private match. You can do capture the leader against one bot and one bot on your team. As soon as the bot picks up the leader the match will be over, as there is noone else who can rescue the leader :-) do this for a few nights and level 100 will be yours.

The Hard Part:

Obtaining the 65 Onyx Medals... this is insanely tough, and rightly so. Gears of War 3 shouldnt be a someone can pick up and be done with in a few days! 

For a total overview of the Seriously 3.0 medal breakdown (all onyx medals and their requirements) please see the following page

Seriously 3.0 medal breakdown (all onyx medals and their requirements)

Alternatively you can see a print friendly version. this may be useful for keeping track!

click here for a printable version of the medals

Some of these are going to be hard to obtain. Some of these not so much. 

The harder Onyx medals will have seperate guides and will be displayed below in a few days time.

What have you found to be the hardest Onyx medals to obtain?

Discuss below your thoughts on Seriously 3.0. Will you be going for it?