Thread:Oneofthosedf/@comment-34326521-20140516193113/@comment-34326521-20140529084918

"Necessary" is up to the individual. Technically speaking, for Ben, it hasn't been "necessary" since he discovered Alien X. He could just turn into Alien X whenever he wanted and stop people from dying. Yet he has killed people since then, IIRC.

Betraying allies is OK.

Heroes sometimes (often, in fact; it's a recurring theme in just about every show and comic book on Earth) team up with villains to stop a bigger threat.

Examples:

The Fantastic Four and Doctor Doom in Fantastic 4: Rise of the Silver Surfer.

The Futurama crew and Mom's three sons in that episode where Mom made the robots rebel.

Ben 10 and Kevin 11 in Grudge Match.

Ben 10 and Kevin in the first episode of Alien Force.

Ben 10 and Darkstar in War of the Worlds, parts 1 and 2.

Ben 10 and Vilgax in Ghost Town.

Ben 10 and (...).

I think you see my point.