In my opinion is a caster a guy who uses (as an example) hcsm, css etc.
and a int buff build is imo ... like a mage warrior or something.
http://tinyurl.com/8rs4z6u this is my caster for the arena With black and crystal magic. You can switch the big hat for crown of dusk, but im a male. And a guy dont wear this. And look at my magic defence, hell i love it.