Complex sentence: Before the events of the video game, her parents are killed by Shadaloo agents at an early age for Juri, also costing her left eye; years later, she has become an agent of S.I.N. who's aliased as "Spider".
Split into simpler sentences: Before the events of the video game, her parents are killed by Shadaloo agents at an early age for Juri, also costing her left eye. Years later, she has become an agent of S.I.N. known as "Spider".