Dope.

Man, my friend would love this item. 

I just noticed something: the item description doesn't say that creatures charmed in this way know that they've been charmed by the wielder--even when the effect ends.

(You know, like it does in the Charm Person spell)

So...that's interesting.

This is so powerful for a Rare item. Also note that, being a rod, it can even be used as an arcane focus.

Does anyone have an explanation of how to interpret "...commanded to do something contrary to its nature..."? 

Example: My players are using this item as an interrogation tool, and I'm wondering if giving up secret information about an organization to your king-for-8-hours goes against their nature.

Quote from HeadBytor >>

Does anyone have an explanation of how to interpret "...commanded to do something contrary to its nature..."? 

Example: My players are using this item as an interrogation tool, and I'm wondering if giving up secret information about an organization to your king-for-8-hours goes against their nature.

 Depends on the individual. It could easily work either way. Consider whether the NPC would be loyal or devout enough to withhold information that could be harmful to the organization; As well as how damaging that would be to them personally. An NPC who was raised in concordance with the organizations motives and morals is unlikely to gossip to one ally about another. Conversely an NPC who views their allies more as their positions in the hierarchy, rather than individuals or comrades, might be more inclined to report to this penultimate authority.

Generally, it is against someones nature to injure, greatly hinder or kill oneself; Unless they are a martyr with a clear and worthy cause, like a devout worshiper of Ilmater or Torm.

If the party is releasing people after using this item on them it would not be unreasonable for information of it's whereabouts to reach a competent thief; Or authority, if it is being used to abuse people by denying them their free will. Something to keep in mind if it becomes too much of a problem.

Quote from HeadBytor >>

Does anyone have an explanation of how to interpret "...commanded to do something contrary to its nature..."? 

Example: My players are using this item as an interrogation tool, and I'm wondering if giving up secret information about an organization to your king-for-8-hours goes against their nature.

Convincing someone that you are a friend and using that to get information from them is what this item was intended for. "While charmed in this way, the creature regards you as its trusted leader" and you can "command obedience" from them. Contrary to their nature, to me, means something that goes against their alignment, not necessary their social position or role. You could command a King to act and bark like a dog, but he still might question why. 

Things that would be contrary to someone's nature depends on their personality and alignment. Self-harm applies to everyone, I would think. Murder, harming children or animals, etc would be contrary to Good and/or Lawful, as well as Neutral, but not necessarily Evil or Chaotic alignments. Things like stealing, adultery, or blasphemy, (such as desecrating a grave or religious idol), would be against the nature of a Lawful alignment. Evil alignments might resist giving away a valuable possession, or performing charitable acts for 8 hours straight. 

yo this be based and poggers.

yeh yeh

this and the helm of telepathy would make it really easy to rule anywhere