Slayer increases your Weapon and Spell Damage for each Fighters Guild active ability you have slotted. This includes the Ultimate, Dawnbreaker, so with the other 4 active skills, that makes a total of up to 5%, 10%, or 15% increase depending on how many points you invest in this passive.
Redesigned this passive ability so it now increases your Weapon Damage by 1/2/3% for each Fighters Guild ability slotted at Ranks I/II/III respectively, instead of increasing your Weapon and Spell Damage by 3/6/9% against Undead and Daedra.
The following passives and player abilities now grant hybrid stats to help improve their viability and accessibility to off-meta builds, because we love them too:
Agility: Now grants equal Weapon and Spell Damage.
Balanced Warrior:
Now grants 660/1320 Armor, rather than 1320/2640 Spell Resistance.
Now grants equal Weapon and Spell Damage values.
Brutal Carange's bonus: Now grants equal Weapon and Spell Damage values.
Concentration: Now grants equal Offensive Penetration.
Dexterity: Now increases Critical Damage and Healing Done per piece worn, up to 2% at the final rank, rather than Weapon Critical (as Prodigy now grants Weapon Critical as well)
Flawless Dawnbreaker's bonus: Now grants equal Weapon and Spell Damage values.
Prodigy: Now grants equal Critical Chance.
Savage Strength: Now grants equal Weapon and Spell Damage values.
Scaled Armor: Now grants 825/1650 Armor rather than 1320/3300 Spell Resistance.
Slayer: Now grants equal Weapon and Spell Damage values.