Complex sentence: In Year Five, after Deathstroke breaks into S.T.A.R. Labs to get the Mother Box for Batman and Lex Luthor, but before he can leave he is greeted by Metamorpho, which result in Metamorpho's death after a tense fight against Deathstroke.
Split into simpler sentences: In Year Five after Deathstroke breaks into S.T.A.R. Labs to get the Mother Box for Batman and Lex Luthor, he is greeted by Metamorpho before he can leave. This results in Metamorpho's death after a tense fight against Deathstroke.