Complex sentence: A tall and muscular bodyguard, trained in hand-to-hand and weapon combat, thanks to Ra's serum (which needs to be taken on a regular basis), Kyle is immortal and able to shapeshift.
Split into simpler sentences: A tall and muscular bodyguard, trained in hand-to-hand and weapon combat. Thanks to Ra's al Ghul's serum (which needs to be taken on a regular basis), Kyle is immortal and able to shapeshift.