I wasn't certain whether to put it here or elsewhere...It's not really a TV series, but not really a movie. It's a Machinima series (not same studio, but same guys who put out the Mortal Kombat series)
I am NOT an anime fan.
I have no idea about Dragon Ball Z except two things...
I think the animation is bad...and I thought the Evolution movie wasn't as bad as all the fanboys made it out to be.
That said...I don't get it.
HOWEVER...apparently there is a new series that's being made with fundraisers and such.
The Youtube link is here
For a Non-fan...this thing doesn't make much sense. People seem to be raving about it, and some fans seem to think it's the greatest thing since sliced bread.
For me the writing wasn't great, the filmwork was decent though, and I wouldn't mind seeing the next one, but it doesn't really make a ton of sense to me.
Is this really the plotline of the old cartoon series? It is of the Machimina series.
So this martial arts guy also seems to have the power to fight them along with the kid?
IF this was true, why weren't there a TON of others who also could do this, surely out of world of BILLIONS there are FAR more than one guy (and later this kid) who actually have the ability to fight these people?
It doesn't make any sense why no one else has the ability to fight these two people...and where did these two people get this type of ability anyways?
They are immortal? How did they get to be immortal of all things?
If you have answers, remember spoilers.
It's not bad despite the writing, but it is pretty confusing to one who has no idea about DBZ stuff.
Didn't bother to watch the whole thing, but it seems to be a live action adaptation of the "History of Trunks" movie. Which means they're probably trying to mooch of the popularity of the insanely popular Dragon Ball Z Abridged web series, of which the most recent episode covered that movie. It's the 4th video, after the Bloodborne let's play and the two Xenoverse let's play episodes. I'd usually be hesitant to say that about something that technically came first, but this came out well after the hype started being built around the release of that episode.
Considering that means it is an adaptation of a movie that explains the backstory of a time traveling side character from a parallel, post-apocalyptic alternate universe, which is core to the plot of the third arc of the series, which is in itself a continuation of an entirely DIFFERENT series, it's no wonder you're confused.
To break down your spoiler:
1.) They are androids. EXTREMELY powerful artificial beings created for the sole purpose of destroying things. They also have the personality of teenagers, and destroy most of humanity because it sounds fun, and because they can.
2.) "Martial arts guy" is, presumably, Gohan. He is the son of Goku, the main character of the main series timeline. The kid would then be Trunks, the son of Vegeta (Goku's rival).
Both Goku and Vegeta are members of an alien race known as Saiyans, a powerful warrior race. Goku and Vegeta are the last surviving pure blood members (the villain of the second arc blew up their planet, and just about everyone on it save four people, two of which were killed in the first arc. Vegeta survived because he was on a mission at the time, and Goku did because he'd been living on Earth the whole time oblivious to his parentage).
Goku and Vegeta are two of the most powerful beings in the universe. As-in "We can blow up a planet if we're not careful how we aim" levels of powerful. Unfortunately, Goku died of a congenital heart defect in that timeline, and Vegeta was defeated and killed by the Androids (17 and 18).
As half-Saiyans, Gohan and Trunks inherit much of their fathers' powers. Moreso, in fact, in Gohan's case, who has a massive untapped potential in the main timeline.
There are others, humans even with the power to wield Ki and fight battles like this, but they're far weaker than the Saiyan characters, save Piccolo, a member of another alien race. Krillin, Yamcha, Tien Shinhan, and a bevy of others who are weaker than them TRIED to fight the androids, but were annihilated in seconds. Piccolo puts up a good fight, but like Vegeta is ultimately defeated and killed.
Gohan and Trunks are not immortal. Though Saiyans are incredibly long-lived (from a human perspective, anyway. I think a lifespan of 300 years or so? I dunno if it's ever explicitly stated but Goku and Vegeta in their 60's still look like they're in their mid-20's.).
Unless you're talking about the line 17 says early on. In which case...they're Androids. You know, robots. They don't age.
I'm not bothering to spoiler any of this because it's pretty basic info about the setting/series and the movie is only tangentially canon in the first place (it's the timeline the main series prevented from occurring. Or, occurring in their timeline.).