Complex sentence: When Odessa is assassinated during a raid at their base, Viktor leads the survivors to safety and approaches Mathiu Silverberg, a tactician and Odessa's older brother, to aid them.
Split into simpler sentences: When Odessa is assassinated during a raid at their base, Viktor leads the survivors to safety. He then approaches Mathiu Silverberg, a tactician and Odessa's older brother, to aid them.