I guess you either missed, or ignored this part eh. I highlighted it for you....
IL law:
(720 ILCS 5/Art. 7 heading) ARTICLE 7. JUSTIFIABLE USE OF FORCE; EXONERATION
(720 ILCS 5/7-1) (from Ch. 38, par. 7-1)
Sec. 7-1. Use of force in defense of person.
(a) A person is justified in the use of force against another when and to the extent that he reasonably believes that such conduct is necessary to
defend himself or another against such other's imminent use of unlawful force. However, he is justified in the use of force which is intended or likely to cause death or great bodily harm only if he reasonably believes that such force is necessary to prevent imminent death or great bodily harm to himself or another, or the commission of a forcible felony.
720 ILCS 5/ Criminal Code of 2012.