The Tech Infantry universe has been around a long time and many of the events that have taken place have been either directly or indirectly influenced by the characters run by players. In most cases a player will control a character for at most a few seasons and if they survive they tend to become important figures in the federation run by the moderator.
Along the way many of them have passed away or have died in action. Nevertheless, in the minds of the players that have been involved with this game for a long time, their efforts will long be remembered.
On the other hand, some of the former characters have survived and are still active. In general be wary of them. Many of them are very powerful and not very nice.
For a list of retired characters broken down by season refer to the link below.