/sci/ - Science & Math

Hello /sci/, I am planning on writing a fantasy series (or, at least, do some worldbuilding for fun). However, except from the use of magic, I want stuff to be somewhat scientifically correct. I don't really expect anyone to answer all of my questions, but I would appreciate some help. I know that this probably isn't the best board to ask about this, but I feel that this is the most intelligent of the boards. Also, english isn't my first language, so excuse me for possible headache.

Show your intelligence and willingness to help humanity, /sci/.

1.One of the kingdoms of the worlds are going to use chakrams as a ranged weapon (http://en.wikipedia.org/wiki/Chakram)), but is it useless against armored enemies? And also, what do you aim for? The throat? Or does it simply suck, and I should let go of the idea?

2.I thought it would be interesting with different kinds of animals in 'cavalry' between the different nations, but what kinds of animal would be plausible? It doesn't have to exist in present era (frankly, since it's fantasy, it doesn't need to have existed at all. Is anything else than a herbivore unrealistic, because of the food required for a big carnivore? I guess that mammalian herd or pack-animals are most likely due to the nature of those beasts. I guess that those facts rule out terrorbirds, huh? Crap. Feel free to come with suggestions.

Part 1/?