We are a group of 5 + me (dm) playing TDE (in German that is). We love role-playing and throughout the last years we developed our own style of playing, which is strongly focused on role-playing rather than fighting. Most characters in our group are not really adept in fighting but more socially oriented.
One of our players (lets call him "A") is very adept in creating new characters and has a lot of fun doing so. Besides the obvious problems with a member of the group often changing a character, I found that the characters had a very high impact on dynamic of the group and the way our adventures develop. E.g. his characters often have very eccentric strokes (extreme cleptomania, extreme naivity and curiosity, disregard for his own life or the setting...) which often create problems for the group. His last character got killed and almost got another players character killed, in a completely quest- and or character-unrelated endeavour.
For me as a DM, that is often pretty awesome, since I am not a big fan of railroading and like it when I really just define the initial setting and the characters basically write the story on-the-go through their actions and responses to the new reactions.
On the other hand, the group always had to have an eye on player 'A's characters (all of his latest three...), to avoid bigger problems for the group. E.g. stop him from stealing from the local baron, not randomly attack enemies he will not win against, not show a dark magician that the group has a very powerful artifact because of naivety etc....
Even though this often leads to great role-playing since the characters are confronted with creative problems and conflicts I could've never imagined, I often feel that this prevents other players from playing their characters in the way THEY want, because they have to basically babysit this other character.
I don't want to force him to build "normal" characters since he obviously likes building more colourful ones and his backstories and ideas are often far more advanced than the others. Still, I don't want the group to resent him, since he often dominates the evening through his actions(last time, half of the group was blocked for almost 2 hours, since he quietly wandered off and randomly started a very unnecessary fight against my best efforts to explain the setting and consequences, couldn't leave, couldn't get help and therefor finally died...).
Do you have a good idea how I could deal with this?