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To "collect" all hosts in the game, you don't have to possess every host in the game, but every type of host must be possessed at least once.
There are no possessable hosts in level one because you're still human.
|Possessable Host #||Host Name||Host Type||Description||Location|
|2-1||Rabbit||??||"A simulated animal designed to put recently separated spectral operatives at ease. These animals are also used to train ops in the art of possessing and controlling a host."||In the virtual reality simulation where you first control Raimi's ghost form.|