Complex sentence: Nefaria sent the four original Ani-Men to kill Tony Stark, however the Spymaster detonated a bomb with which he had intended to kill Stark, and the resulting explosion killed the Ani-Men instead.
Split into simpler sentences: Nefaria sent the four original Ani-Men to kill Tony Stark. However, the Spymaster detonated a bomb, which was intended to kill Stark, and the resulting explosion killed the Ani-Men instead.