Avatars

An avatar is the look chosen for the player character by the player.

Avatar Card Trading
You can have a max of 98 Avatar Cards per save.

Avatars are player characters that in God Eater 2 have 3 equipment sets tagged to them. In God Eater Burst, NPCs in general including Avatar Cards never use Impulse Edge. To trade the avatar cards, go up to a player in multiplayer and press triangle. There are play rewards only in GEB. They are F-tickets, gainable in multiplayer, although sometimes they are found as rewards in challenge mode or DLC.

Rebirthing
This will allow you to start the game from the beginning and can be done through Main Menu/Import Save Data.

Advantages
(Note: alternatively you can do this via a hex editor).
 * Able to change gender and looks.
 * Able to change name.
 * Able to read missed NPC conversations
 * All items and equips are kept if Transfer All option is used.
 * Avatar cards and Mission records are intact.
 * Able to play fairly with low ranked players in multiplayer.

Disadvantages
Thus you cannot rebirth and instantly view the part where your character speaks.
 * Unable to change Code Name, which is displayed in missions.
 * All story progression related stuff will revert to the beginning.
 * Equip craft list reverted to rank 1.
 * Looks/Clothes will be reverted to rank 1.
 * Only able to equip rank 1 equipment, higher rank equips will be locked until you reach the rank.
 * All entries in Norm and Room Terminal reverted to rank 1.
 * Hairstyle selection reverted to rank 1.
 * Clear tick on missions will be gone.
 * Unable to play higher ranked missions offline/multiplayer as they would be locked again.

Thus, rebirthing is not recommended unless one is desperate to change looks. (This only applies to GEB, as it's possible to rebirth while retaining your story progress in GE2 & GE2RB by choosing the second option after picking which save file you want to rebirth).

Code names in any God Eater games are permanent and cannot be changed in order to prevent the players from using a same exact savedata in multiplayer, as well as prevent the players from cloning their own characters into Avatar Cards.