Lycanthropy, specifically wererats.

[Dr. Zoom]

Is there a spell someone can cast to see if a person has lycanthropy?

Yes. Find an 11th or 12th level ranger who has shapechangers as a favored enemy. Get him to cast Detect Favored Enemy.

 

[Vaxalon]

If he loses his ID how can he try to regain his human form.

He no longer loses his identity after he voluntarily changes. At that point, he has merged with the beast, and can learn how to control the change.

 

[da chicken]

Is there a spell someone can cast to see if a person has lycanthropy?

In theory, locate creature keyed to werewolf or wererat would work. You might be able to look for a lycanthrope, but not likely. Detect thoughts would work as well, although you may have legal problems with this. Spells such as divination or even augury might help you to narrow your search area.

Beyond that, you'd have to create a new spell, either detect lycanthrope or detect disease, although the latter would not detect a true lycanthrope. Detect lycanthrope could be based off of detect animals or plants, and detect disease should be based on detect poison.

 

[The_lone_gunman]

After the first transformation, the character can choose to voluntarily change into the form. If he does choose this, however, he instantly becomes the alignment and disposition of that form (some kind of evil I believe for wererat), and thus becomes an NPC (unless of course he is one of the "good" were creatures or you are playing an evil campaign). When he chooses to change, he has to make the control shape skill check or perhaps loose himself again in the animal form. There is some detailed rules in the MM but I don't have it with me here at work.


TLG

 

[FANGO]

There sure do seem to be a lot of misconceptions about this out there...

It all seemed pretty obvious to me when reading through the lycanthrope section a couple times. First of all, you don't even know you're a lycanthrope (unless you know what one is and knew that one was biting you and inferred that you may have the disease or something) until you make a wisdom check DC 15 after an involuntary change. When you make an involuntary change, you take on the alignment and mindset of the creature for the time being, which is subject to DM interpretation and you basically become an NPC for the duration of the involuntary change (unless you are aware of your disease, in which case you can make a control shape check DC 25 under a full moon or DC 20 at any other time (you are also subject to an invountary change whenever you are reduced by 25% of your hp in combat (that is, each time you reach 3/4, 1/2, or 1/4 hp))). In order to control the affliction, you must gain ranks in the control shape skill. When you make your first voluntary change, your alignment is permanently changed to that of the creature, most likely along with a suitable change in personality. You can never control yourself during an involuntary change (except for making the control shape check DC 25 or 20 to return to human form) as, by definition, they are involuntary. If the character you are talking about would like to control his changes, he must learn the control shape skill.

Any other questions are answered fairly explicitly in the section in the SRD about lycanthropes.

 

[Pielorinho]

A couple of points.

When the lycanthrope template is applied to a creature, the creature's type changes to "shapeshifter," right? So if you want to find out whether someone is infected, simply cast "hold person" on her. Cheesy as all getout, but I think it works.

And while I believe the lycanthrope is under DM control, this is a place to tread carefully. If you take control of a normally good PC and have her go on a slaughter, the game may become not very fun for the player. Be considerate of your players' fun; if you want to have the lycanthrope go on a rampage, you may want to talk to the player first, out of game.

I had exactly this situation come up in my game a few months ago. The player was really unhappy with the situation until I assured him out of game that his character was not now a murderer of innocents. Instead, I played up the cowardly nature of wererats: a new wererat especially has no reason to know that she is invulnerable to normal weapons, and so is likley to act like a scared cunning rat for awhile.

Daniel