*Note: This is a bio on Future Trunks, not the one from the Buu Saga*

Name: Trunks

Age: Unknown (Due to Hyperbolic Time Chamber)

Eyes: Blue

Hair: Purple (Yellow when Super Saiyan)

Race: Half-Saiyan Half-Human

Gender: Male

Father: Prince Vegeta

Mother: Bulma Briefs

Siblings: None

*Side note: This is VERY complicated and VERY confusing*

Not much was known about Future Trunks until the movie The History of Trunks. 
We will start when he was 13, a time where Goku has died from a heart disease
and most of the Z Fighters have been killed by the Androids 17 and 18:

At the age of 13, Trunks asks Goku's son, Gohan, to train him. After a year of
training, and despite all of Gohan's efforts, Trunks cannot reach yet the 
Super Saiyan (SSJ) level, even if his fighting skills improved greatly; 
it's like he needs some shock or anger to switch to the SSJ mode. His Saiyan 
heritage can be clearly seen through his way of fighting, but neither him 
nor Gohan are a match for the Androids. 

One day, Gohan brings Trunks with him into a fight against the Androids so 
that Trunks can observe and learn their fighting techniques. Unfortunately, 
one of the Androids attacks Trunks, and to defend his young student, Gohan 
interferes and looses an arm before the two saiyans hide underground to escape
from the Androids.

A few weeks pass, and another attack by the Androids occurs. This time, Gohan 
knocks down Trunks to keep him safe. Trunks is the only hope for the Earth, 
but he's not ready to fight the Androids yet. Gohan faces the Androids alone 
and dies in battle

When Trunks wakes up and searches for Gohan, he finds his body laying in the 
mud of the ruins of the city that was just attacked. The shock makes him 
lose control and he turns SSJ for the first time. This was in fact the shock 
he needed. 

Three years of conflicts passes. The time machine is almost ready, but Trunks 
hears about a new massacre provoked by the Androids not very far from him. 
His mother tries to make him stay at their hiding place. If he dies now, 
there is no hope. Trunks, feeling confident in his own strength, prefers 
trying to rescue the people in the present and flies right into the place 
where the Androids are. Twenty minutes later, the Androids leaves him for 
dead. He's brought back to the hospital where he stays in the coma for 5 days.

When he wakes up, he realizes that he will probably never be able to defeat 
the Androids in the traditional way, and accepts to go into the past to change
the events that lead to this war. That decision would change his life forever.

His mother gives him the medecine that will cure Goku's desease. She believes 
that if Goku is still alive when the war will start, he'll be able to defeat 
the Androids. Trunks has another purpose by going into the past: He wants to 
meet the father he never knew: Vegeta.

And this is how we first see him in the TV show: he appears as a young adult, 
turns Freeza into Kibbles 'n' Bits and annouces to a group of stunned 
Z Warriors the arrival of Goku three hours later. He'll reveal to Goku the 
events of the future and gives him the medecine that will perhaps change the 
future. He then teleports himself three years in the future to be there 
when the war begins.

Unfortunately, his actions in the past won't change his future home. He just 
created a new storyline where the changes can be seen, while the storyline 
where he comes from remains unchanged.

His presence in the past also provokes the arrival of an organic android 
(a bio-droid named Cell), who was stuck into the future and had killed Trunks 
to steal his time machine and come back in the past.

For Cell, this already happened, but not for Trunks. In fact, Cell killed 
Trunks because he needed to absorb the Androids to transform into his perfect 
state, and...in the future...Trunks had killed the Androids! This is why Cell
needed to warp to our time.

Trunks knows that one day he'll go back to the future and will destroy the 
cyborgs, but that Cell will then kill him and steal his time machine to 
come back in the past.

The presence of Cell in the present time pushes Trunks, Goku, Vegeta and the 
others to train harder than what the would have done if Cell hadn't appeared. 
So, Trunks is confident: When he'll meet Cell in the future, he will kill 
the biodroid.

But Cell has other plans: He wants to become perfect (and manages to do so by 
absorbing the Androids), but also, wants to prevent Trunks from returning 
in the future to destroy the Androids. He learned from Trunks that each 
time someone travels in the time, a new future is created.

Therefore, Cell thinks that if he kills Trunks before he returns to the 
future, the (not perfect) biodroid in that future will be able to 
absorb the Androids and won't have to go in the past to do so...

Cell organizes a tournament during which he manages to kill Trunks before 
being killed by Gohan. Trunks is resurrected and returns in his future. There 
he destroys easily first the cyborgs, then Cell, three years later. 

    Source: geocities.com/xxgamrguyxx3