Bloodborne is easily the darkest and most twisted game FROM has ever made, some of the stuff I've seen and stuff that is implied to happen before I arrived made me go "Oh [parasitic bomb]" more than a few times. Bloodborne may start out gothic horror game but turns full on Lovecraft mid to late game. And I LOVE it.
Father Gasgoigne's family, and the children of the Orphanage. Yesh.
Also soft and hard caps have been discovered.
(Note physical Def goes up regardless of what stat you level)
Vitality: Increases HP
Soft Cap: 30, little to no increases past the Hard Cap of 50
Endurance: Increases stamina (Unlike souls there is no more equip burden)
Soft/Hard Cap: 40 (Little to no increase past that)
Strength: Required for wielding certain weapons, increases damage with weapons that scale with strength.
Skill: (The Dexterity of Bloodborne) Required for wielding certain weapons, increases damage with weapons that scale with Skill.
Bloodtinge: Required for weilding certain weapons and firearms, increases damage with weapons that scale with Bloodtinge, however it mostly affects firearms.
Arcane: Increases damage with certain items and scales off certain weapons. Also effects the damage of certain Hunter's Tools (Magic).
The four attack stats all have a soft cap of 25/30 and hard cap of 50.
As for transformation that was rumored, you don't transform sadly but it does increase your damage for a time at the cost of reduced defense. The Beast Claw gauntlet weapon uses this mechanic naturally I hear.