Maxima

Maxima was a Canadian soldier who led a normal life until he found out that his comrade-in-arms Rocky was killed in an incident involving NESTS. To avenge Rocky, he decided to sacrifice his previous life; he had his face and name changed and his "ordinary" life destroyed. To infiltrate the cartel without being recognized, he had his body cybernetically modified by Dr. Makishima, hence his codename of Maxima.

He infiltrates NESTS and is assigned to be the partner to K'. They both defect from the cartel after K' encounters his clone, Krizalid, and grows sickened by the organization.

(Source: Wikia)