The real-life crosier (also spelled crozier) is a stylized, often ornately-decorated staff that is a symbol of the governing office of a high-ranking Christian priest. This staff generally comes in three forms: hooked, in the shape of a shepherd's crook (curled off to one side); tau, in the shape of a T with downwards-curving arms topped by a small cross; and serpentine, with a pair of sculptured serpents or dragons curled back to face each other in an upwards-facing U with a small cross between them.
The fantasy version of the crosier tends to resemble a bastardized version of one (or several) of the above, with a small sphere or circular symmetrical "shepherd's crook" bisected or topped by a large cross (the overall profile will often resemble a Celtic cross). Some versions may just be a large cross mounted on the end of a staff (with the whole staff resembling a Latin cross, like the Pope's ferula). Another common fantasy variant has a scepter-like head topped off with a small cross.
Priests and fantasy priestesses are often depicted holding a crosier. Some may instead be depicted wielding a generic mage staff; such examples should not be tagged crosier.
Tag crosier for the priest's staff described above—both the real versions and the fantasy variants.
As a general rule, any fantasy staff that appears vaguely Christian-like (i.e. festooned with crosses and Christian motifs) will also tend to qualify.
Avoid tagging crosier for 'generic' looking staves that may be better off tagged staff or mage staff.
Fantasy priest(ess)es are sometimes depicted holding a 'generic' crystal or gem-tipped staff without any religious trappings, one that would not look out of place being wielded by any other magic user. These examples should be tagged mage staff and not crosier.
Fire Emblem characters belonging to the priest or cleric class lines tend to just wield generic mage staves because of Nintendo being allergic towards the depiction of crosses and other religious iconography.
Do not tag shakujou (i.e. Buddhist staves) with crosier.
The Pope's staff is a Papal ferula, but this can be tagged with crosier for now.
