During the big reveal of Bloodborne at E3, we caught a glimpse on the saw-cleaver which will be one of the weapons included in the game, and of its ability to transform. Today we also learned that said transformation will actually have a role in the game.

Game Director Hidetaka Miyazaki actually explained how that will work in an interview on 4Gamer, also mentioning that it's bound with one of the main themes of the game, which is "exploring the unknown" (the others are "a battle to the death" and "new online gameplay").

About the theme “exploring the unknown"  I spoke about earlier, I believe the concept should be applied to gameplay elements. The tactical factor of the new "active battle" is part of that, but we also want to include unknown elements in various areas of gameplay, for instance in character builds and the strategy the player will use. We'd like players to have fun stumbling their way through the game and finding out those unknown elements.

For example I can explain this by talking about the weapons that can be used together with the gun and that we define "gimmick weapons" . In the CG trailer shown at E3, we introduced the saw-cleaver weapon. That weapon has an unique shape and can also transform, and its features also change depending on the transformation.

Using those different transformations is an integral part of gameplay, and there are even unique attacks with special effects that can be executed only while the weapon is in the middle of a transformation. I think that there will be a lot of room for exploration on how to master those weapons.

Looks like Bloodborne will have plenty elements to distinguish it from the previous Souls games, and this definitely seems to be a major one. Miyazaki also seems to imply that the game will take a radical steer away from the linear approach, so I wouldn't be surprised if the freedom of exploration extended to the game's world as well.