A supporting NPC throughout most of the game, Gehrman looks over the Hunter's Workshop within the Hunter's Dream. He will provide advice regarding where to go, specifically Old Yharnam to locate a chalice and to ascend Oedon Chapel to uncover certains truth concerning the Healing Church. While initially portrayed as a mentor of sorts to the player, Gehrman can potentially be fought near the backstretch of the game. As the night begins to come to an end and the full moon recedes back into the distance, Gehrman poses the choice to the player that he allow them to return to the ''waking world'' by killing him/her, which is implied to be mercy on Gehrman's part so as to help the player escape from their duty of The Hunt. If the player accepts, Gehrman will execute him/her and the player will be shown waking up to the dawn in what is implied to be the real world.
If the player refuses, however, then Gehrman will be fought and may potentially function as the final boss of the game.
Despite his frail and aged appearance, Gehrman quickly proves to be an incredibly capable Hunter. While he typically walks slowly, he is incredibly agile and will often dash towards and from the player. His is equipped with the Burial Blade, which at first resembles a large scythe, and a unique blunderbuss.
Gehrman is separated into three stages. The first has him exclusively use his Burial Blade in its scythe form. His scythe attacks cover a wide range, with one particular attack that has him extend his scythe to pull the player towards him. If hit by this attack and brought within reach, Gehrman will then typically follow through with his three-hit combo. Each attack of the combo is delivered methodically with a distinct pause in between each attack, allowing players to efficiently dodge each if timed correctly, however if hit by the first attack then it's extremely difficult to avoid the second. If the player is far away enough, then Gehrman will be shown to place his scythe on his back as he charges up a 720 degree swing. The attack is extremely powerful and will likely kill the player if caught by it, however Gehrman will perform this attack even should be the player be out of its range completely, thusly allowing players an easy opportunity to get some hits in as he recovers.
Gehrman will flinch from every melee attack, however after enough attacks he will perform an attack wherein he vertically slices up then down. There'll usually be an animation showing him to briefly charge up akin to the 720-spin, however the charging period is significantly shorter and will sometimes be executed immediately if the player continues to attack him.
After enough damage Gehrman will enter his second stage, wherein he transforms his scythe into a one-handed curved greatsword and equips his blunderbuss in his other hand. In this stage Gehrman becomes more aggressive and will push forward on the attack more frequently. Each attack from his greatsword doesn't do as much damage as an attack from the scythe, however his combos may now contain more attacks. He still has a three-hit combo which involves him charging forward with each attack in his attempts to keep in range with the player even should they try to escape. His other most common combo includes a long flurry of attacks that, if caught within, almost certainly spells the player's death; he finishes the combo with a shot from his blunderbuss. While much faster and ultimately more deadly, his flurry combo doesn't cover nearly as much ground and is thusly easier to avoid than his regular 3-hit combo. It's also arguably one of the easier attacks to parry due to the sheer number of attacks the combo consists of.
Even outside of combos he will shoot the player with his blunderbuss; it covers a wide spread, but the damage it deals isn't as alarming as his melee attacks. He will often shoot the blunderbuss following a roll towards the player, though he will sometimes lead the roll into a swipe with his curved greatsword. Dodging the attack regardless of what it is usually makes for a reliable counter dash attack against him.
Gehrman's final stage is initiated with him becoming enveloped in a white aura; when transitioning into his third stage he will vulnerable to attack for a few seconds. During this phase Gehrman now combines all of his available attacks and will routinely switch between his scythe and curved greatsword, sometimes mid-combo even complete with its own transform-attack; he is also now immune to flinching from player attacks. What's more he will add some completely new attacks to his repertoire for this final stage. With the scythe he now has access to an extremely powerful sweep attack, which he will first charge for a second before then performing a single wide-range swipe. Another equally decimating attack involves him leaping high into the air, and then cleaving through the air itself to cause a long strike towards the ground. The attack itself is practically invisible, and dodging it is reliant on timing the dash the very moment after he swings his scythe. Getting hit by it has a high chance of killing the player immediately.
His curved greatsword itself doesn't gain any new attacks, however he does gain the ability to stun the player with his blunderbuss and then potentially follow through with a visceral attack. When preparing to stun the player he will be shown to quickly load his blunderbuss with a special bullet and then fire an orange projectile at the player. Unlike regular blunderbuss shots the projectile is a single bullet and doesn't have any spread. If hit by it the player will be stunned exactly as if they were parried, and should Gehrman be able get close enough to the player in time will enact a visceral attack; as one would expect the visceral attack has an extremely high chance of killing the player outright.
Gehrman's final new attack is one that has him standing still as he slowly powers up before unleashing an explosion from his person. The charging phase leaves him vulnerable to attacks, however due to the vast range of the explosion it can prove risky to continue the assault. The explosion is his most powerful attack and will always kill the player outright if it hits.
Should players have thusly rejected Gehrman's offer and then proceeded to beat him, the ending will show a creature descending from the moon; it will then embrace the player upon landing. From there it shows the player character taking Gehrman's place (quite literally as they sit in his very wheelchair) as the night begins anew.
However if players consumed at least three (of a possible four) of the Third Umbilical Cord items, beating Gehrman will then lead into another boss battle right after against the 'Moon Presence' creature that descends from the moon after it rejects the player character. Otherwise Gehrman will function as Bloodborne's final battle.
Upon beating the Moon Presence, the ending will instead show The Doll picking up the player character, who has transformed into an infant 'Great One'. Beyond some additional blood echoes, there is no other mechanical benefit to beating the Moon Presence.
- For as much agility Gehrman clearly possess', he is still funnily enough shown to walk with a limp due to his right peg leg.
- With enough Insight, Gehrman can sometimes be found outside the Hunter's Dream workshop asleep, muttering to himself. His mutterings involve him talking to Master Laurence.
- Pre-boss fight Gehrman can be attacked like any other NPC, though instead of dying he disappears into a puff of smoke and will reappear the next time players return to the Hunter's Dream. Attacking Gehrman has no effect on the story nor his boss design.
- Dying against Gehrman will always end with him saying ''You must accept your death... Be freed from the night...'', adding to the idea that Gehrman is in fact trying to 'save' the player from a worse fate.
- Whence the Gehrman boss fight has been triggered, players can use the respective Bells to summon help or join another player's game to assist while within the Hunter's Dream. Players still cannot invade/be invaded, however.
- His appearance during the boss fight differs from his regular appearance, with Gehrman now shown to be wearing a top hat and cape. His cape resembles that of the Charred Hunter attire, which has a description stating such garb was worn by Hunters during the burning of Old Yharnam, implying Gehrman's involvement in the event.
- Beating Gehrman will reward the player with the badge necessary to unlock his Burial Blade and attire in the shop, though the armor pieces are of his garb worn in his wheelchair as opposed to the boss fight. His blunderbuss isn't unlocked, however. If players choose to be executed, then they will not receive the badge.