Jake

Jake is a modified human who served the Union as a member of its Assassination squad, where he is partnered with Mary. He is one of the earliest modified humans and antagonists introduced in the series.
Jake is one of the most powerful successful experiments created by Dr. Crombel. He is Mary's partner; the two of them make up the assassination unit of the Organization/Union.
Jake is usually egotistical and extremely aggressive, which gets him scolded by Mary. He thinks very little of failed experiments such as M-21 and M-24. He likes brutality shown in his elimination of everyone in the hospital.
Jake was shown to be very powerful, especially in comparison to M-24 and the minimally-transformed M-21. Jake forced the scientists to experiment on him in order to improve his transformation. In his full transformation state his powers were ten times greater than that of Mary's powers.