The first DLC for Code Vein, aptly titled DLC1: Hellfire Knight, is now available for $9.99 individually or as part of the game's $24.99 season pass. As you may have deduced, it introduces a new boss called the Hellfire Knight, but that's far from the only bit of new content.
The Hellfire Knight is more than just another boss fight, for one. It also comes with "Horror Hunting Trials" which challenge you to fulfill certain objectives while fighting. For example, the Knight Monarch Overthrower Trial requires you to defeat the Hellfire Knight without fainting more than five times (your AI partner can revive you as long as they still have HP). Completing Trials will unlock cosmetics, weapons, items, and the fiery Surt Blood Code. You can view some of the new cosmetics here.
A new map for the Depths has also been added: Fiery Oblivion. This area seems to be styled after the Crown of Sand, and it contains the Achilles Blood Code which you can unlock by thoroughly exploring the Depths and collecting all the relevant memory fragments.
You can get the map for Fiery Oblivion in a new room attached to the Provisional Government Outskirts section of the Crypt Spire. Fast-travel to the Crypt Spire, grab the map, then bring it to Davis at the hub to access it. As it happens, this DLC room also contains the first fragment of the Asclepius Blood Code. The other two fragments will be added in the next two DLCs, so you'll need to own and play all three to unlock Asclepius.
Whether you're new to Code Vein or coming back for more with this DLC, here are 10 Code Vein tips that'll help you conquer this anime dungeon-crawler.