The competitive skill ranking used in Halo 5: Guardians was designed by in part by the same person that created the matchmaking systems on various Blizzard and Activision games, according to a senior developer at 343 Industries.
Posting on Twitter, studio head Josh Holmes was asked if the Halo 5 team got ideas for its ranking system from Hearthstone, given the similarities between them.
"Halo 5's [competitive skill ranking] system was designed by Josh Menke," Holmes replied. "[He] also worked on Hearthstone."
Menke, who is currently ladder and matchmaking designer at Activision, clarified that he was more closely involved with StarCraft 2, and left 343 before the Halo 5 beta became available.
"I like the improvements 343 has made since," he continued. "Shameless plug: come to my GDC 2016 talk and see how different ranking systems fit into the big picture."
The Halo 5 release date has been confirmed as October 27. Microsoft's has said the game will require players to download a day one update. Those that purchase the digital version of Halo 5 from the Xbox Store and pre-load it can install the day one update before it launches using the Xbox One's Instant On mode.
The day one update weighs in at around 55 GB (46 GB for the game and 9 GB for the update), according to reports.