The Seinaru is one of the Three Factions withing Shinobi Story Online, the other two being Kokonerasu, which is in essence Anti-Seinaru, and Shinobis as a whole.
The Seinaru consists of two sections: The Samurai and the Priests/Priestesses. The Samurai are the brawn of the faction, akin to the DPS/Tank Spec in any MMO for reference; while the Priest(esse)s are the Support class, or the Heal/CC Spec.
SAMURAI: You'll be the primary fighters of the faction. Most if not all samurai have a sense of honor, duty, and a code that they live by. They range between those who would rather die than decline a duel, to those who simply seek to live a good, honorable life.
You are focussed on melee as a samurai. You might get ranged techniques, but I can not stress enough that at core you are a swordsman and will almost always do better at melee range than a shinobi of equal rank, assuming you wield a katana (Or two).
Which brings me to customization. Samurai have uniformic robes that they wear, many out of choice to represent their rank. It goes as following
SAMURAI CUSTOMIZATION: To get a sense of uniqueness, you are fairly restricted as far as clothing goes, as you'll usually be wearing your robes. You can choose from many fighting styles though, with one or two swords, or even with other weapons such as the naginata.
PRIEST: You'll be the support of the group, keeping the samurai strong and healthy. The main attraction of Priest/esses is twofold; You get to play an inherently good character without much gray area, and you will become much greater at healing than any medic, through the use of Light.
FAITH: Most priestesses, and I say this because being female is preferred for this half of the faction, believe in some higher being. They don't all have to believe in the same thing--they don't even have to believe in a "god", but they almost always believe that something is up there or around them that is good.
PRIEST CUSTOMIZATION: Priest/esses get a much broader scope of uniqueness compared to samurai, in regards to their clothing. They have no hardset uniform unless the current faction leader makes it so. Most wear soft or light colors, but that's only to mirror their uplifting personalities.