Which preposition to use with cerberus

of Occurrences 5%

It opened at once, revealing the big body of a Celestial, evidently the Cerberus of the establishment.

in Occurrences 2%

You will get quiet possession of your house, it is true, for I have put a Cerberus in it, that is quite equal to his task, difficult as it may be, and who has quite as much relish for a bill of costs, as any squatter can have for a trespass; but without some such guardian of your rights, I would not answer for it, that you would not be compelled to sleep in the highway.

within Occurrences 1%

The chairs are worth moresome day they'll fetch twice that; but, really, I must throw a sop to that collector-Cerberus within me.

Which preposition to use with  cerberus