Original Curse Seal
In the Naruto series, the Curse seal has different types, but basically there are 2 stages.
- Stage: the seal activates and gives you a boost to your jutsus, enhancing your chakra flow.
- Stage: the seal will result in a physical change and adds different abilities to you, again, the chakra flow increases.
Abuse/Heavy Usage of the Seal will wear the bearer down finally.
Curse Seal on SL
There are currently 2 stages, each is related to the stage in the original series but different in how you get and what you can do with it.
Note that also there are currently no subtypes, but this might change.
The curse seal is specifically designed to be for evil shinobi, so it's unlikely a good shinobi can use it, but there may be exceptions like Anko.