The Master Serum is made up of four incomplete Serums, each belonging to a branch. Gideon Cahill hid the master Serum from Damien Vesper and split the unfinished Serum into four parts—the four branch Serums. He gave each of the Serums to each of his four children, according to their strengths. It altered and enhanced their DNA, giving them each the skills their branches are known for.