Abilities

Normal abilities are shown in blue(good) or red(bad) and unique variant abilities are shown in yellow with a star.

A weapon or piece of armor may have abilities, which enhance its performance beyond its raw or baseline statistics. The item's abilities are displayed in small boxes below the item's statistics bars. Abilities can be classified into four broad categories:

• A weapon may carry a chance of inflicting status effects on its targets.
• A weapon may carry attack speed increase (ASI), charge time reduction (CTR), and damage bonus.
• A piece of armor may carry a health bonus or movement speed increase (MSI).
• Armor may also carry extra protection from damage or status.

Unique variants (UVs) on an item are one kind of ability. Other abilities are inherent to the item type; for example, all Wild Hunting Blades carry a beast damage bonus. Other abilities are granted by accompanying equipment; for example, handguns receive attack speed increase from the Nameless Poncho armor.

Status-Inflicting Weapons

Some weapons carry a chance of inflicting a status effect (curse, fire, freeze, poison, shock, sleep, stun). This ability is always inherent to the weapon; it cannot be granted through UVs, armor, or trinkets. In most cases, the status is inflicted on monsters (or enemy players, in PvP), but in some cases the status can also afflict the user. Some weapons inflict status only on charge attacks, not on regular attacks. Status abilities are rated on two scales: the chance of causing the status, and the intensity of the status once inflicted. For example, Plague Needle offers "Slight chance of causing Strong Poison".

Other Offensive Abilities

There are three other offensive abilities that can enhance weapons:

• Swords and handguns, but not bombs, may carry an attack speed increase (ASI) or decrease. ASI affects the speed of regular (non-charge attacks). In one set of tests, each level of ASI was found to add around 4% to attack speed.^[1] Other tests suggest that each level of ASI adds about 3.6% to sword combo speed and handgun combo speed. Those data also show ASI to have a small effect on the number of charges that can be executed per minute.

• Any weapon may carry charge time reduction (CTR), which reduces the amount of time required to charge the weapon. In one study, each level of CTR removed around 7.5% of the weapon's baseline charge time.^[2] Another study found each level of CTR to add about 6.4% to sword charge speed and 6.3% to handgun charge speed. All weapons automatically receive CTR: Low when they reach heat level 5 and CTR: Medium (replaces the Low from level 5) when they reach heat level 10.

• Any weapon may carry a damage bonus. Some damage bonuses apply against specific monster families (construct, gremlin, fiend, beast, undead, slime). Other damage bonuses apply against all enemies: all six monster types, special monsters such as Lord Vanaduke, and enemy players in PvP. Against a monster of a particular family, general damage bonus behaves exactly like family damage bonus. For example, when attacking a slime with a sword, "Sword Damage Bonus: Medium" and "Damage Bonus vs Slimes: Medium" are equivalent. Each level of bonus adds an average of 7% extra damage.^[3]

These three offensive abilities are rated on a six-point scale, shown below. Each verbal descriptor has a numeric equivalent. Low, Medium, High, Very High, and Maximum! weapon UVs are obtainable; Ultra is not.

Offensive bonuses are additive, but cap at +6 (Maximum!). For example:

• Two +1s (Lows) add to give +2 (Medium).
• One +2 (Medium) and one +3 (High) add to yield +5 (Ultra).
• One +4 (Very High) and one +3 (High) add to +6 (Maximum!), not +7 (over Maximum!).

For each ability, all sources of bonus add together, toward the same +6 limit. As a detailed example, consider a gunner with these items equipped:

• Perfect Mask of Seerus (gun ASI+1, gun CTR+2)
• Shadowsun Slicker (gun damage+2)
• Nova Driver at heat level 10 (CTR+2), with UVs for CTR+3 and construct+4

The Nova Driver then has these total abilities:

• ASI+1 (Low)
• CTR+7 (Maximum! — no better than CTR+6)
• damage+6 (Maximum!) against constructs
• damage+2 (Medium) against other enemies.

Health and Movement Speed

Armor grants health to the user. For example, 5-star armor grants four health points at heat level 1, and five health points at heat level 5. Ancient Plate Mail grants an extra three health points, compared to other 5-star armors. Scarlet Shield grants two health points. Heart trinkets can also grant up to six health points each. Battle Sprites can grant up to six health points (through perks). Health bonus is not achievable through UVs.

Ancient Plate Helm reduces the user's movement speed; Mercurial Helm, Mercurial Demo Helm, Black Kat Cowl, and their associated armor suits increase the user's movement speed, while some battle sprites can increase the user's movement speed. Movement speed increase is not achievable through UVs. Movement speed abilities add, much like offensive abilities; two Lows add to yield a Medium, and two Lows and a Medium add to yield a Very High, which is the highest level currently achievable. Each level of bonus appears to affect movement speed by about 4%.^[4]

Damage and Status Resistance

Helmets, armor suits, and shields can carry UVs that grant them additional resistance to certain damage types or status effects. Low, Medium, High, and Maximum! damage and status UVs are obtainable; Very High and Ultra are not obtainable as UVs. These UVs behave quite differently from weapon UVs, and are arguably not abilities in the proper sense. Each UV simply increases that armor piece's resistance to that damage or status. In the defensive summary at the bottom of the character window, the increase is displayed as a lengthened statistic bar, rather than as a separate box. The lengthening suggests a four-point scale:

It does not appear that the combined contributions from various armor pieces are capped at Maximum!, as offensive abilities are. For example, it appears that two Maximum! piercing protections offer more total protection than one Maximum! piercing protection.

Each level of damage resistance bonus seems to add about 10% of the defense of a "standard" piece of armor (for example, Skolver Coat for piercing), up to 40% for a Maximum! UV. (Test data can be found here, here ^[5], and here ^[6].) The data are consistent with the visual lengthening of the damage statistics bars. The damage resistance offered by trinkets is not well studied.

Tests of status resistance suggest that a 5-star trinket is equivalent to a Medium on the four-point scale, and that a highly resistant armor (such as Volcanic Demo Helm) is equivalent to a Maximum!^[7] The highest status resistance that can be displayed in the character's defensive summary is eight points. However, tests suggest that resistance above eight points is meaningful; it is simply not displayed.

The damage taken from a status seems to decay exponentially with the amount of resistance: four points negate roughly 40% of the status damage, eight points negate around 65%, etc. The effects of resistance on status duration are not well studied. Curse resistance seems to reduce the duration and the number of items affected. Data from resistance tests are aggregated in a Spiral Knights forum thread.^[8]

Bugs

• Equipping two pieces of equipment that have abilities that cancel eachother out will still display a nonsense ability in the equipment summary tootip. It will be in red and have a positive bonus description. This means that the ability is simply null. This is because the visuals for self-cancelling abilities has not been programmed.