Assassin's Creed: Brotherhood/Abilities, perks, bonuses

As you level your character up, you will be rewarded with different abilities, perks and bonuses, all of which can be set in your Profile Sets. You will eventually have more enhancements than slots, so experiment with the ones that best suit your play style, the style of the players in your current session and the map you're on.

Abilities
Abilities can be used at any time during the sessions and must be activated by pressing the button corresponding to the ability. You get two ability slots in your Profile Sets, and there are currently six you can obtain through leveling. Each ability also has a cooldown timer after you use it, and it will be displayed in your ability icons on the screen by putting the number of second left until you can use it inside the icons.

Disguise
The Disguise ability changes your appearance to one of the other character skins at random. This is useful to confuse a pursuer, who has to determine who is target is visually when he gets close enough. This is best used while standing near one or more characters so it's not obvious to the pursuer that it's still you.
 * Level acquired: 2
 * Duration: 12 seconds
 * Cooldown time: 60 seconds

Sprint Boost
This ability increases your speed while in high profile by 30%. Sprint Boost will give you a better chance of catching your target in chase mode or escaping your pursuer in pursuit mode.
 * Level acquired: 3
 * Duration: 5 seconds
 * Cooldown time: 60 seconds

Smoke Bomb
The Smoke Bomb creates a smoky cloud 3.2 meters in diameter with a small pause between activating the ability and its creation. This will stun other characters, allowing you to escape, stun your pursuer or kill your target. You can also use the ability in hiding.
 * Level acquired: 8
 * Duration: 3 seconds
 * Cooldown time: 60 seconds

Hidden Gun
The Hidden Gun can be used on a character you're locked on to. Hold down the ability button to focus your aim and release to fire. Getting a kill in this way isn't worth a very high score, but if your target is far away or constantly running around, it may be easier and quicker to use it. You can get a slight score bump for waiting until your target is airborne before pulling the trigger.
 * Level acquired: 11
 * Aim time: 1.5 seconds
 * Cooldown time: 90 seconds

Morph
The Morph ability changes all characters within a 3.2 radius of you into your character's skin. Try to find a group to use this one to increase the probability that your pursuer will pick the wrong target. You can also use this ability to counter your target's Morph ability. When you use it on a group that has been morphed already, all the NPCs will change to you skin, revealing your target.
 * Level acquired: 14
 * Duration: Permanent
 * Cooldown time: 60 seconds

Poison
This ability lets you poison your target for a delayed kill and a 200 point bonus. It's dangerous to use this ability, because it takes five seconds to kill your target, and if another pursuer takes them out before the poison gets them, you lose the kill all together.
 * Level acquired: 20
 * Duration: 5 seconds
 * Cooldown time: 90 seconds

Perks
Perks are passive enhancements, and you get one slot in your Profile Sets for them. These perks are always in effect and there are currently two perks available through leveling.

Enhanced Auto-Bash
This ability increases the number of characters you can run into while in high profile without stumbling. This is useful when you're in chase or pursuit mode and any slow down could result in failure. You can always just use the unarmed hand button to shove people as you're running, but this perk will help you out if you can't get to it in time.
 * Level acquired: 15

Blender
The Blender perk changes one character in a group to your character skin when you blend in with them, unless one of them already has the same skin as you. This is a good way to quickly fool a pursuer you know is close to you without wasting one of your abilities to disguise yourself or morph the whole group.
 * Level acquired: 19

Streak bonuses
Streak bonuses only go into effect after you've obtained a streak in the session. The two types of streaks are kill streaks and loss streaks. Kill streaks are when you kill a series of targets in a row and loss streaks are when you have a series of lost contracts in a row. There are two slots in your Profile Sets, one for each type of streak, and there are currently four streak bonuses available through leveling.

3 Kills Streak
This bonus is applied once you have killed three targets in any manner. The bonus adds an additional 100 points to your score for each successive kill until you lose a contract.
 * Level acquired: 5
 * Streak type: Kill streak

3 Silent Kills Streak
This bonus is applied once you have killed three targets silently (you will see the Silent score). The bonus adds an additional 300 points to each successive silent kill until you lose a contract or kill a target without the Silent bonus.
 * Level acquired: 13
 * Streak type: Kill streak

Extra Sensitivity
This bonus will increase the precision of your compass until you make a kill.
 * Level acquired: 4
 * Streak type: Loss streak

Reset Cooldown
With this bonus active, any abilities currently on a cooldown timer will be reset every time you die, until you make a kill.
 * Level acquired: 12
 * Streak type: Loss streak