Complex sentence: However, Heihachi proves stronger and, realizing the woman he loved is gone, regretfully kills her, and eventually leading his own downfall, then will sparks the Mishima clan civil war as of the present.
Split into simpler sentences: However, Heihachi proves he his stronger and, realizing the woman he loved is gone, regretfully kills her. Eventually leading to his downfall, then sparks the Mishima clan civil war as of the present.