1. Consent can act as a defense in criminal law by negating the intent element of a crime. The Indian Penal Code describes excuses like consent that are not considered offenses.
2. Consent is defined broadly in Sections 87-91 of the IPC as a general defense and is also mentioned as a defense in specific sections related to offenses against the body and property. Where consent is obtained through fraud, fear or from an unsound person, it is not valid consent.
3. For offenses like murder, the consent of the victim only reduces the charge to culpable homicide, rather than absolving culpability. In rape, lack of consent is a key element of the offense as amended in 2013.