- "That guy ain’t human. We must have shot him at least five times, stabbed him like six. He had knives sticking out of his fucking chest, man! Didn’t even slow him down."
- ―Timothy Swank
As well as soul power and a Servant power, a Reaper will also gain several unique abilities relating to the control of their servant's physiology. Most of these abilities require the reaper to be able to touch their servant, although a few are always in effect.
Regeneration and Vigor
Perhaps the most notable of the powers of a servant is their ability to regenerate from any wound within minutes or even seconds. Almost as notable, especially for young servants is the ability to break down their own tissue to temporarily gain incredible strength. These two abilities work very well together, as regeneration can repair the damage to joints and muscles caused by the strenuous overuse of them that vigor allows while also replacing the fat and muscle matter consumed to power it. If vigor is used without regeneration, the servant will take on a deathly appearance with ashy skin and sunken features as the padding on their bodies runs out. Both regeneration and vigor require reaper-to-servant contact and last about half an hour unless terminated early.
Resurrection
If a servant suffers brain death, they will not be able to act on the outside world in any way. However, they will still be able to think and communicate with their reaper, just like when the reaper first contacted them offering to make them a servant. At this point, the reaper will be able to recreate the servant's body starting as a tiny speck of brain matter from wherever they are. This means that as long as a reaper gets away safely and their servant is able to successfully kill themselves, they can escape from any threat.
Delayed Pain
Reapers do not have the ability to prevent their servants from feeling pain, hunger or exhaustion. However, they do have the ability to delay the effects of any of these feelings and spread them out, so that for example a single excruciating injury might be spread out to several days of milder aches and pains. In theory, a reaper could just put off pain forever, but in practice this runs the risk of a disruption of contact for too long causing enough pain to make the servant go insane.
Because of the immense amounts of exercise that a servant can do in combat under the effects of vigor, they will usually be completely ravenous as the recuperate following a major battle. They will also often feel very tired and irritable, especially if their reaper was injured. The inevitability of pain will follow a servant even to an entirely new body, preventing a servant from simply killing themselves to escape it. After a few years servants seem to develop basically unlimited pain tolerance, rendering the point irrelevant.
Prevention of Brain Death
By nature, even if a servant suffers an injury that renders their body unable to supply nutrients to their brain, their brain will still remain intact and functional. This is beneficial in that it allows a servant to continue the fight even after suffering heart injuries or severed veins, but it also leads to the risk of a servant being defeated by decapitation followed by freezing and storing the brain, which leads to the servant being unable to think, act or use their power but still counting as alive an thus impossible to resurrect at another location. This ability may also be required to function as a servant at all.
Aging
Getting old is optional for servants. The body physically aging can be stopped and started by their reaper. Most prefer to show their age and try to stop before overly severe negative effects set in. Aging cannot be reversed. Because of the choices that servants make about their age, it can be extremely confusing to figure out who is senior, since an old servant might look their age, ten years old or anywhere in between.
Other effects
In addition to the abilities listed above, reapers are also able to induce a number of other effects in their servants, such as causing them to fall asleep or temporarily not feel tired.