Trunks: Savior from the future
Trunks is the son of Vegeta and Bulma, a seemingly unlikely couple. He first appears as a young man from the future to warn Goku and the Z-Fighters about the impending danger of Dr. Gero's androids. Before he encounters them, however, he has a run-in with Frieza and King Cold. He kills the two almost effortlessly. He warns Goku about the disease he will eventually get, and of the androids, and then goes back to his own time.The future that Trunks comes from is bleak. He is the only surviving Z-Fighter... Goku having died of heart disease, and the rest of them killed off by the androids. The populace of Trunks' future are scattered, living in fear. Trunks is their only protector.
About three years later, Trunks returns to the past to help fight against androids 19 and 20 (Dr. Gero). What he doesn't understand, though, is why these two androids aren't the same ones that destroyed his world. The androids from Trunks' time, 17 and 18, appear later, when activated by Dr. Gero, who they destroy. Unbeknownst to the Z-Fighters, there is a more powerful enemy lurking. Cell, who will gain his full power when he absorbs androids 17 and 18, then attacks, blah blah blah, and is destroyed by Gohan. Confused yet? Good... cause I'm not done yet...
Now on to Chibi Trunks. Chibi Trunks is the baby who was present throughout all the stuff I described above. He was born 2 years after Future Trunks first visited Goku.