The original Brotherhood of Evil members were as follows....
A French scientist who experimented on animals, and a rival of Niles Caulder, the man who became the Brain had his body damaged in an explosion, but was saved by one of his experiments, who transplanted his still living brain into a self-contained unit to keep him alive.
Part of those plans involved recruiting others to help him.....and the Brain started with the one he knew best!
It was Mallah that saved the Brain, and had him transplanted into the jar that saved his life. Mallah often worked to keep his friend alive, and to do whatever the Brain needed him to do.
But, the team had another member, that the Brain also helped create....
Laura became the headmistress of a Paris girls' school (which was also a front for the Brotherhood....and what school kid didn't feel their teachers were evil?). First, Madame Rogue used her actress talents to disguise herself, but the Brain enhanced her powers in Doom Patrol #90 (September, 1964, by Drake and Premiani). This story also gave hints of her split personality...and, a little later, her love for the Chief.
the Doom Patrol as well in Doom Patrol #121 (September-October, 1968, also the issue which introduces Zahl). It took some time, but Robotman did return, and with the help of Beast Boy (who was using the name of Changeling, and working with the new Teen Titans), finally ends the menace of Rogue and Zahl in New Teen Titans #13 to #15 of November, 1981 to January, 1982 (though a form of Rogue returns with Gemini, in later Brotherhood incarnations, as does the Brain and Mallah, with more Brotherhood recruits).