Bungie has bid an emotional farewell to the Halo universe it created ten years ago.

The US developer marked its 20th anniversary last week with Bungie Day, a celebration of all things Halo.

"Thank you for making our 20th Anniversary, and this year's Bungie Day, kick so much ass," Bungie's community manager Eric "urk" Osborne wrote on Bungie.net.

"As we prepare to become fans of the universe our studio began creating more than ten years ago, it's nice to know that we'll be counted among such esteemed company.

"Some might consider the upcoming transition a bittersweet occasion punctuated by a sense of loss and sadness. We feel otherwise. Halo is in great hands... yours.

"Halo is yours now. In many ways, it always has been. Its new caretakers will strive, just as we did, to be worthy stewards but you have the package. Hold these characters and stories and worlds to the same unflinching standards you did while we were at the helm, but allow them all to blossom and change and grow in the ways that they must."

Halo is now the responsibility of Microsoft's internal studio 343 Industries, which is currently managing the development of remake Halo: Combat Evolved Anniversary, due out this November, and next year's Halo 4, announced at E3 last month.

Halo 4 marks the beginning of a new Halo trilogy.

Bungie, meanwhile, is now fully focused on its next game, for publishing giant Activision  and suggested it will be a long while before we know what it is.

"We'll be undergoing a metamorphosis of our own," Osborne continued. "Very soon Bungie.net will change, culminating with the launch of our next universe at some unknown time in the future.

"The first small steps will be taken soon, with Halo playlist management changing hands on August 2nd, the very same day we plan to deploy our parting thoughts on the last twenty years through a ViDoc titled, 'O Brave New Worlds.'

"Afterwards, we'll be going dark on our studios next major endeavour  the creation of a brand new universe. You'll still have a home here should you choose to stay, but our next project demands an unwavering focus. We owe it to ourselves to make something better than we ever have before. We owe it to you, as well.

"So, this isn't a goodbye. It isn't The End. Instead, it's the very beginning of a new journey that will stretch the limits of what we are capable of. Ancient engines are now rumbling deep within the heart of our studio, and their energy will power us through the upcoming darkness. Like all dark times ours will be broken first by a single strand of light  a tether reaching out to bind us all together again.

"One day, we will awaken in a wondrous new place and we will remember just what it was that drew us together at the beginning of it all. We will look up to the heavens, and find hope.

"Thank you for everything.

"See you starside."