Strikethrough

While wielding a Two-Handed Weapon, or while wielding a Bastard Sword or Dwarven Axe in your main hand and a Shield, Orb, Rune Arm, or nothing in your offhand, your attacks can Strikethrough. When your attacks can Strikethrough, every attack has a chance ("Strikethrough Chance") to hit an additional target. By default, players have a 20% Strikethrough Chance (which can be improved through feats and enhancements). If your Strikethrough Chance is over 100%, you are guaranteed to hit a second target (if in range) on your attacks, with a chance to hit a third. The cap to Strikethrough is 400% (or 5 targets).

Strikethrough was introduced in Update 45 and replaced Glancing blows.

Strikethrough Chance
Two Handed Fighting: +60% chance
 * Feats

Improved Two Handed Fighting: +30% chance

Greater Two Handed Fighting: +30% chance

Perfect Two Handed Fighting: +30% chance

Natural Fighting: +60/30/30% chance

Angry Arms: +5/10/20% chance
 * Enhancements

Mad Munitions: +5/10/20% chance

Focus Wide: +50% chance

Improved Second Strikes: +5/10/20% chance

Followthrough: +50% chance

Improved Second Strikes: +5/10/20% chance

Hand and a Half Training: +5/5/5/5% chance

Dance of Death: +50/100/200% chance

Dwarven Axe Training: +5/5/5/5% chance

Great Weapon Aptitude: +5/10/20% chance

Greater Domain of Destruction: +5% chance

Malicious Weapons: +5/10/20% chance
 * Epic abilities

Wild Weapons: +5/10/20% chance

Unbridled Fury: When activated, +100% chance


 * Filigrees
 * One Against Many (3 pieces): 20% chance

Special attacks that strike through
Some special attacks are able to hit the secondary target(s). Based on.

Barbarian

 * Cracking Attack (FB)

Bard

 * Frozen Fury (Warchanter)

Cleric

 * Warpriest Smite

Druid

 * Nature's defensive stance allows strikethrough. While in bear form strikethrough works regardless of what weapons you wield.

Favored Soul

 * War Soul Smite

Fighter

 * Kensai enhancement - Shattering Strike

Monk

 * Finishing moves
 * Fire/air/water/earth strikes
 * Enhancement - Ninjutsu line (modify touch of despair finishers)
 * Enhancement - Elemental words (all-consuming flame, porous soul, static charge, winters touch)

Paladin

 * Smite evil

Feats

 * Stunning Blow
 * Trip

Epic abilities

 * DC - Smite the wicked
 * FoTW - Boulder's Might
 * LD - Lighting mace, volcano's edge. I didn't test Anvil of thunder but I assume it works to.
 * SD - Executioners strike
 * US - Celestial Mandate (Couldn't test hate effect)
 * US - Draw them out (Couldn't test hate effect)

Special attacks that don't strike through
TBD