Short answers, pulled from the story.
Stilicho was a Roman army general born around 359 who considered himself fully Roman despite having a Vandal cavalry officer father. He followed Nicene Christianity rather than Arianism and began his career as an embassy envoy to King Shapur III in Ctesiphon in 383.
Stilicho married Serena, the niece of Emperor Theodosius I, after returning from his diplomatic mission to Persia. Their union produced three children named Eucherius, Maria, and Thermantia.
On Easter Sunday 402, Stilicho defeated Alaric at Pollentia while besieging Mediolanum. He captured Alaric's camp and wife but allowed Alaric to escape with most of his men.
Stilicho was executed on the 22nd of August 408 alongside his son Eucherius following a mutiny by the army at Ticinum on the 13th of August 408. Rumors had circulated about plans to assassinate Rufinus and place Eucherius on Arcadius' throne after the 1st of May 408.
The death of Stilicho removed the only general capable of breaking Alaric's siege or maintaining frontier defenses effectively. Without him, Honorius adopted a passive strategy that led to the Gothic army breaking through Rome gates in August 410.