Angel of Fury's second ability is a leaves-the-battlefield ability. Because it works only from on the battlefield, it behaves differently than the _Lorwyn_ Incarnations. When Angel of Fury is put into a graveyard from the battlefield, it will look back in time (to the point just before it left the battlefield) to see if its ability triggers. That means the following: — If Angel of Fury lost its triggered ability while on the battlefield (due to Snakeform, for example) and then was destroyed, the ability would not trigger. Angel of Fury would stay in its owner's graveyard. — If Angel of Fury had its triggered ability when it left the battlefield, but lost it when it was put into the graveyard (due to Yixlid Jailer, for example), the ability would still trigger. Angel of Fury would be shuffled into its owner's library.
If Angel of Fury is removed from the graveyard after the ability triggers but before it resolves, it will remain in its zone when its owner shuffles their library. Similarly, if a replacement effect has it move to a different zone instead of being put into the graveyard, the ability won't trigger at all.