https://insider-gaming.com/assassins-creed-red-exclusive-details/
"To start, the Assassin’s Creed franchise as a whole isn’t moving to a new engine necessarily, but will be using a substantial evolution of it named the ‘Anvil Pipeline’. Sources explained that the Anvil Pipeline allows all of the various Assassin’s Creed studios (of which there are many) to work from one unified branch, rather than having different versions and branches. The most means that moving forward, Assassin’s Creed will benefit visually from the lines of ray-traced global illumination and virtual geometry.
The move to the Anvil Pipeline has meant that the teams have had to completely overhaul everything in the series, too, including animations, its parkour system, dynamic weather, and more.
Combat in Assassin’s Creed Red was described to me as being somewhat similar to Valhalla, but featuring a lot more gore, including blood, and decapitations. Stealth also plays a major role in Red, somewhat akin to Splinter Cell, the player can extinguish torches, hide in tall grass and bushes, and even go prone whenever they please.
Footage provided to Insider Gaming under the condition that the footage does not go public also showed a major evolution to the Valhalla Settlement feature. In Red, players will be able to build their settlement in a big way named the ‘Hideout’. The Hideout is where the player will be able to build, at their own will, the likes of an armory, dojo, alter, and more. These buildings are customizable, too, from being able to pick the building location, to being able to choose your roof design to the interior layout and where you can display the likes of your weapons and armor can be displayed."