Can anyone tell me the name of the collective "mini ninja" type toys the kids are playing with lately?

I'd like to know the name of the figurines so I can find them to purchase. They are about an inch tall, made of molded plastic, and come with the names of different elements (i.e. "moon", "sun", "fire"). To me they look like aliens, but my seven year old son just calls them mini ninjas. Thanks!