Increase the damage your Physical, Bleed, Poison, and Disease Damage over time and channeled abilities do by 20%. It doesnt inrcrease dmg from channeling abilities like dizzy swing or mist form or soul ultimate.

What does deadly strike buff?

Although a PVP reward Armor Set, Deadly Strike is one of the best Stamina DPS Sets for PVE Builds. The Set's bonuses boost your Weapon Damage and Weapon Critical. Its fifth piece bonus increases the damage your Physical, Bleed, Poison, and Disease Damage over time and channeled abilities do.

Does deadly strike buff snipe?

Deadly strike does not buff uppercut or snipe. They have cast times but they are not classed as “channelled” abilities.