Quest for the Holy Relic and any living weapon equipment, like Batterskull, have what appears to be a contradictory interaction regarding where the searched for equipment end up. When a Quest for the holy Relic has five quest counters on it, the controller of the Relic can sacrifice the Relic to search through his library for an equipment card and put it into play attached to a creature controlled by this player.

With most equipment this is where the situation ends, but equipment with the living weapon keyword puts a 0/0 germ token into play and causes the equipment to become attached to the germ. So where does this equipment end up?

The important fact to keep in mind is that when a spell or ability resolves it will resolve completely. Other abilities can trigger during this resolution, (hint: living weapon is a triggered ability) but these triggers wont go on the stack until after this spell or ability has resolved. So in this interaction, the Quest ability will resolve, put the equipment into play attached to a creature controlled by the controller of the Quest. This will cause the living weapon ability to trigger, but as mentioned this trigger will not go on the stack until after the equipment has been attached to another creature. When the living weapon triggered ability resolves, a 0/0 germ will be put into play and the equipment will move over to the germ.

So, technically speaking the equipment comes into play attached to one creature, stays on this creature briefly, and then moves over to the germ.