- "A powerful and deadly cutting and thrusting weapon, perfect for slicing and swiping through even the toughest armored vehicles or infected hides. "
When either Mercer or Heller activate this ability, an elongated double ended blade forms from the base of the right elbow, turning their arm into a giant razor sharp cutting weapon.
The blade is extremely effective in close contact, and although the area of effect is very localized, the blade's basic attacks dish out higher damage than those from any of the other powers. While this power may be utilized against basic infantry units, its true destructive capability is in attacking vehicles and large infected creatures such as hunters or brawlers. 
Alex Mercer can perform many moves by upgrading this ability, whereas James Heller has to gain mutations for upgrades. As he mutates his ability, the attacks, damage dealt and the appearance of his blade change with each level.
The following are upgrades for the Blade power available to Mercer:
- Blade Air Slice: An aerial drop attack, Alex falls with a bit of a spin to enhance the slicing capabilities of the Blade. This ability can destroy any non-boss (or building) unit in at most two direct hits. It is the most powerful single strike available from the Blade.
- Blade Frenzy: Mercer lashes forward, unleashing a series of slashing attacks from a standing position, slicing while running for a few steps. Can be manually interrupted by a Diveroll.
- Blade Sprint Frenzy: An upgraded alternative to Blade Frenzy which allows Mercer to perform the same attack as Blade Frenzy but while sprinting. The slashes from Blade Sprint Frenzy deal slightly higher damage than slashes from a Blade Frenzy. It can cut through crowds of human-class enemies at a very high speed, but it cannot be interrupted manually.
The Blade is a close combat power and is capable of dealing large amounts of damage to heavy targets. Although it doesn't quite match the Claws in terms of raw speed, the Blade's attacks are still fairly quick and they deal more damage than any other power. Even the Hammerfists cannot match the Blade's damage potential against a single target.
A completely charged Air Slice attack causes very heavy damage and is an efficient means of dealing with toughened enemies. However the attack can be difficult to execute effectively. The Air Slice involves dropping on top of an intended target, therefore its tracking capability is highly dependent on the starting altitude when executing the attack. This makes it difficult to perform against helicopters, since they can often out maneuver Mercer and Heller with their speed and ability to ascend. From the time the attack is initiated to the landing on the target, Mercer can be shot down by enemy fire. Another downside to the Air Slice is that upon landing, Mercer will pause a short while to recover, which is often enough delay for quicker enemies to counterattack.
Blade Frenzy moves allow for a quick series of strikes to rapidly finish off a large foe, or simply dash through enemies, dealing massive damage to anything the Blade touches while evading the short but deadly reaches of certain opponents.
The main issue with the Blade, especially in the first Prototype, is that it is tailored more towards engaging single, tough opponents. Prototype 2 makes up for that shortcoming by introducing the Tornado as an all-round, medium-reach chain of attacks that utterly ruins anything organic in the path of a spinning Heller.
|Blade Power||Biological Imperative||none|
|Blade Air Slice||Children of Blacklight||1,000,000|
|Blade Frenzy||Children of Blacklight||700,000|
|Blade Sprint Frenzy||Shock and Awe||1,200,000|
James Heller has improved Blade ability in Prototype 2 compared to Alex Mercer in Prototype. The Blade Frenzy moves have been streamlined into a collective ability known as the Blade Tornado, in which Heller spins with his Blade arm fully extended, creating a radius of cutting that slices anything in the way of his path as he rotates towards a given direction. Heller can also leap towards a target while in mid-air, cutting anything in his trajectory with the Blade. Note that doing a Blade Air Slice, as well as a Blade Tornado will automatically take away one arm from a healthy Brawler without any stunning or trapping with Tendrils. The Blade Air Slice's damage against Armors is also weakened and is overall less effective than Hammerfists' groundspike divebomb attack against tightly packed enemies.
Level 1 - Blade acquired.
Level 2 - Blade range increased 15%.
Level 3 - Blade Tornado gains an additional spin.
Level 4 - 25% increase in Blade damage.
- Of all Powers, the Blade is the only one that has three consuming styles on human-class enemies while the others have only two.
- The first level of Heller's Blade resembles a military combat knife. The last level brings a drastic cosmetic change with a very salient curve to the Blade's edge.
- In Prototype 2, this is the only power that has two different animation after an attack. Heller either slides his blade on the ground, leaving a mark and also making sparks or he will do a fast whip-like move to get the blood off the blade.
- Doing a Blade Tornado in the middle of a sprint will execute it with an additional spin, which stack on upgrades that give it more spins.
- In order to fully utilize the power of the tornado spin, it is advisable to first target the enemy. This will ensure the tornado attack focuses on the targeted enemy and not other nearby things like civillians and walkers.
- On the intro of Prototype and on his last battle in Prototype 2, Mercer can be seen dual-wielding his Blade and a single Claw.