Starter's Guide

Jadeon
High DPS and AoE, but limited in Support. Best class for damage.

Lupin
High Seal. Equal attack, damage and support capabilities. One of the most annoying classes to face, in the opinion of DPS users. (I recommend this class for beginners)

Incense
High DPS. No support and seal capability. Mostly relies on summons to deal damage (Based on my impression of this sect)

Vim
Constantly skips turns. Extremely high DPS, though.

Skysong
Heals, revives. Also buffs teammate's physical attack and defence.

Longevity
Very strong at sealing. Also #1 target for other sealers. Also #1 target for being focus attacked.

Poisoner
A lot of DPS, and uses poison.

Southern Border
Heals, revives. Buffs magical damage.

Character customisation and Username
JD:NF has a very high level of customisation allowed for new characters. I'm not very familiar with the UI because I don't care about my characters' looks, but there seems to be a 'Look ID' that logs all of the changes that you made to your character. It's a 16-digit HEX number, so you can play around with that.

Neither the look nor the username of the character matters in-game, as per all games.

First Spirit Beast
After you've started the game, you will go through a basic tutorial. After that, something happens and you get asked to pick a first pet, a choice between 3 pets that all look ugly, mostly just from the lack of effort put into their models. Back to the point, it doesn't really matter which one you pick, because the stats of all 3 are exactly the same. Either way, they will be replaced by other pets later on.