How fast do Realms specialty priests advance?
The official answer in 2nd edition AD&D is that specialty priests use the druid advancement table (although their XP total does not reset), gaining a level for every 500,000 XP earned beyond 20th level (5,500,000 XP; note that FRA has a typo and says 8,500,000 instead; this is *wrong*). Many DMs use the cleric advancement table instead. In Demihuman Deities, there is a new optional advancement table for specialty priests (except druids), crusaders, monks, and shamans.