Rune

Runes are demonic sigils in Doom (2016) and Doom Eternal which upgrade the Doom Slayer's intrinsic abilities.

Doom (2016) includes twelve distinct runes, each of which must be earned by finding its corresponding rune stone, a green glowing monolith bearing the runic mark, and defeating the ensuing "rune trial", a battle which occurs in a small enclosed space disconnected from other game play areas. The runes are passive permanent upgrades, but only a certain number can be equipped at a given time, based on the Praetor suit's current capabilities. A maximum of three runes can be equipped when the Slayer is at full power; one rune can be equipped after completing the first trial, while the second slot requires four completed trials and the third slot requires seven completed trials.

Doom Eternal includes nine distinct runes, which are unlocked by interacting with crucifixes of Maykr design. The runes can be unlocked in any order, but only one rune may be unlocked from each crucifix. The Ancient Gods, Part One added three support runes that are unlocked by completing the Slayer Gate challenges in each level.

Multiplayer
Runes are introduced in Update 6.66, replacing hack modules. Runes now last throughout the user's life instead of being single-use items, and they are unlocked via player progression. Their effects are greatly simplified as well, as they are no longer ranked by tiers and some effects from hack modules have been combined together. Up to three loadout slots are provided to the player once unlocked, which are used to select a single rune for each match.

Runes are not available in Clan Arena and Infernal Run.

Doom Eternal
You can now choose the rune that is unlocked when you find a rune's location, allowing these to be earned in any order.

Support runes
Added with The Ancient Gods, Part One, support runes take up a specialized slot and can be awarded either after clearing a Slayer Gate in Part One or finding their hidden locations. Only one support rune can be equipped at a time. The Slayer begins The Ancient Gods, Part Two with all three support runes in his possession.

Trivia

 * The single-player runes of Doom (2016) are loosely based on s and diabolical seals used in, as derived from various medieval s and the well-known 17th century occult book, the . None of the runes exactly match actual known sigils, however.
 * The "Intimacy is Best" rune resembles the Dopefish.