This is a guide about why to choose a ninja (guide doesn't have taos in it.)

First: Why choose ninja over a Trojan.

Trojan is a lot like the ninja. They can both wield two weapons but the ninja is stronger and the trojan has better defense. It is also easier to choose weapons for the ninja because they have only the ketenes. Trojans have multiple choices of weapons. But usually everyone uses: A blade and a club, two blades, two clubs, a sword and a club and two swords. About a trojan VS a ninja. As I already said the ninjas are better at attack then defense so they will kill fast. But the trojans have lover attack but higher defense so they can defense the ninjas' attacks. Then we come to the skills. The ninja has his/her dual katana skill and some toxin skills that are useful. The trojan has cyclone (can run fast), accuracy (to triple hitting accuracy) and the golem (transform into a robot. All the three of them are XP skills so they are useless if the bar isn't full. Then the troijan's weapon skills. They must be bought and there are a lot of them. The good thing is that some of them will affect without pressing anything. They will just randomly work. A good example is the rage (club skill).

Second: Why to choose over a warrior?

The warrior can wield one weapon and a shield or a two handed weapon. Their amour is the heaviest so they have much better defense then a ninja has. The ninjas have their ketenes that are stronger weapons than the warriors weapons (any weapon but not backsword, bow or a katana.) And the ninja can wield two of them. About a warrior VS a ninja. The ninja has high attack but the warrior has high defense so to would be a pretty even for both. Choosing a weapon to a warrior is pretty easy. First at low level you use a shield and any one hand weapon (not backsword and katana). Usually everybody uses a club, a blade or a sword but there are other weapons too. Then at high level you use two handed weapon. About skills. The warrior has accuracy (same as the trojan), superman(damage decupled for a short period), shield(defense tripled), roar(increase XP for teammates nearby)and flying moon(magic attack).Ninjas has: Counter-Kill(ninja attacks to the enemy's back)and Shuriken Vortex(ranged attack).

Third: Why to choose ninja over an archer.

The archers can kill multiple monsters whit one shot. That makes them good p-levelers (power-levelers).They can fly so they are hard to reach. Whit their bow and arrows they can kill far away but the ninja must come close (or use poison star or if XP bar is full shuriken vortex).About an archer VS a ninja. The archers can kill far away but the ninjas have a skill just for archers. Choosing a weapon to an archer is easy because the can only use bow and arrows. About skills. The archer has: Scatter(hit multiple targets),rapid fire(fire a lot of arrows fast),intensify(greater attack),senior and super fly(fly 40 and 60 seconds, elementary fly(fly 40 sec) and arrow rain(100% damage).The ninja has: The skill to keep the archer on the ground the archer bane(archer can't fly) and fatal strike(powerful strike, monsters only).

That is it. I don't say that you should choose the ninja but it is pretty good against everybody. Fire and water taos where not in this guide.