Kripp and Krippi are teammates playing Diablo 3 in hardcore mode. Hardcore mode means that once you die, you lose your character and all the items on it and have to start over.
They had just accomplished the world first Diablo (final boss) kill on Inferno (hardest difficulty) in hardcore mode. This is a big deal because:
- This is extremely hard, requiring extreme amount of skill and dedication.
- In an hour, a patch is going live that is going to nerf the difficulty of inferno in various ways (since for most people it's near impossible), and anyone killing Diablo on hardcore/inferno post-patch will have an easier time.