When you use the supernatural ability turn undead, you make a turning check (1d20 + your Charisma modifier), and the maximum Hit Dice of the single Most Powerful Undead Affected (PH 159) is dependent on your effective cleric level. Then you determine your turning damage (2d6 + your effective cleric level + your Charisma modifier), which determines the actual number of Hit Dice of undead that are affected by your turning. If the maximum Hit Dice of the Most Powerful Undead Affected and the turning damage result both equals or exceeds an undead creature's Hit Dice, that undead creature's turned. Then
If you have twice as many levels (or more) as the undead have have Hit Dice, you destroy any that you would normally turn. (PH 159)
The Rules Compendium rephrases but doesn't change this, saying
If you have twice as many levels or more than the target creatures have Hit Dice, you destroy any that you would normally turn. (146)
If, instead of turning undead, you rebuke undead
Undead that would be turned are rebuked instead, and those that would be destroyed are commanded. (PH 159, RC 147)
The Player's Handbook goes on to say
At any one time, the cleric may command any number of undead whose total Hit Dice do not exceed his level. (159)
The Rules Compendium changes this some, saying
At any one time, the controller can command any number of creatures whose combined Hit Dice don’t exceed his level. (147)
In all cases emphasis mine. Other references in the section Turn or Rebuke Undead (PH 159-60) refer to cleric level. Therefore, determining if an undead creature's destroyed via turn undead doesn't depend on your effective cleric level but on your total character level, and that means determining if an undead creature's commanded via rebuke undead doesn't depend on your effective cleric level, either.
- Seriously? I mean, I'm not missing anything here--this really means just sum your levels in all your classes and compare that sum to the undead creature's Hit Dice, right?
- Do monstrous Hit Dice count as character levels when determining if the creature possessing the monstrous Hit Dice who can turn or rebuke undead destroys or commands an undead creature?
If both answers are yes, then, for example, Yogi--a legendary bear (MM2 137-8) who's been the target of the spell awaken [trans] (PH 202) and who has 2 levels of cleric and picked rebuke undead instead of turn undead--, can command 24 Hit Dice of undead creatures, each with 1 Hit Die, via his ability to rebuke undead.