Bane

formula needed for Spell Damage Increase because it is a true conversion, a 10% increase means your spell damage is increased 10% and so on. The intensity range of the Spell Damage Increase item property is 1% to 18% for found rings and bracelets. The apparent maximum is 30% for special items (e.g., War of Shadows Invasion Spellbooks).

Qualifiers

As with most code over time, Spell Damage Increase is not as straight-forward as it seems. It does affect Poison Strike and Wither, but it does not affect Pain Spike or Holy Light. It works with Word of Death, as the spell is not dependent on a secondary ability check, e.g. like Pain Spike, which involves Spirit Speak, or Holy Light, which involves Karma.

Calculating Spell Damage

A character's skill level of evaluating intelligence is the first thing that comes into play in calculating the base spell damage. The formula for how much spell damage your getting from your Evaluating Intelligence is this: ((evaluating intelligence * 3) / 100) + 1
The next factor involved in spell damage is intelligence. The formula for this is 1% spell damage increase for every 10 points of intelligence, or (intelligence / 10) and drop the decimals.
The next factor is the inscription Skill bonus. This bonus only takes effect when a character has achieved the level of Grandmaster or higher in Inscription. This is a 10% increase in the base damage for Magery Spells.
Spellweaving spells Arcane Empowerment and Reaper Form can also increase spell damage.
And finally, factor in any SDI imparted from items.

Bane Items

Weapons

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Runic Craftig, Reforging & Imbuing

As of today (2013-10-15), Bane is a property available on Boss Loot only. It is not possible to craft items with the Bane property nor to imbue it onto items.

Item Properties
Stat Modifiers	Dexterity Bonus • Hit Point Increase • Intelligence Bonus • Mana Increase • Stamina Increase • Strength Bonus
Regenerations	Hit Point Regeneration • Mana Regeneration • Stamina Regeneration
Hit Effects	Assassin Honed • Blood Drinker • Battle Lust • Hit Cold Area • Hit Curse • Hit Dispel • Hit Energy Area • Hit Fatigue • Hit Fire Area • Hit Fireball • Hit Harm • Hit Life Leech • Hit Lightning • Hit Lower Attack • Hit Lower Defense • Hit Mana Drain • Hit Mana Leech • Hit Physical Area • Hit Poison Area • Searing Weapon • Splintering Weapon • Hit Stamina Leech
Historic	Ruin • Force • Might • Mystic • Power • Vanquishing • Newbified
Damage Types	Physical Damage • Fire Damage • Cold Damage • Poison Damage • Energy Damage • Chaos Damage • Direct Damage
Magic	Casting Focus • Faster Casting • Faster Cast Recovery • Lower Mana Cost • Lower Reagent Cost • Mage Armor • Mage Weapon • Resonance • Spell Channeling • Spell Damage Increase • Spell Focusing • Spell Consumption
Weapon	Damage Increase • Swing Speed Increase • Use Best Weapon Skill • Weapon Speed • Hit Chance Increase
Archery	Balanced • Damage Modifier • Lower Ammo Cost • Range • Velocity
Death & Theft	Blessed • Cursed • No-Drop/No-Trade • Insured • Owned By
Damage Dealing	Damage Eater • Rage Focus • Reactive Paralyze • Reflect Physical Damage • Soul Charge
Other	Artifact Rarity • Defense Chance Increase • Durability • Elves Only • Enhance Potions • Gargoyles Only • Lifespan • Lower Requirements • Luck • Mana Burst • Mana Phase • Night Sight • Self Repair • Shard Bound • Skill Bonus • Strength Requirement • Uses Remaining • Weight
Negative	Antique • Brittle • Cursed • Ephemeral • Prized • Massive • Unwieldy • Unlucky •