Complex sentence: In "Sonic Adventure", Eggman learns that a legendary monster, Chaos is trapped in the Master Emerald, he seeks, finds and shatters it, freeing Chaos in the process.
Split into simpler sentences: In "Sonic Adventure", Eggman learns of a legendary monster trapped in the Master Emerald, Chaos, and seeks out the Master Emerald. Upon finding it, he shatters it, freeing Chaos in the process.