Which hero are you? (Game)

Nope! Not Shadow Blade.

Divine Rapier ;)

Put me on your back. I will help you stay safe.
You can kill people before they kill you. (Only one that I'm not sure of)

Put me in your hands, I will put them in their place.
You will be killing them, "putting them in their place."

Put me on your back, your team will thank you.
Your team will sarcastically thank you.

And the enemies will be afraid to gank you.
You will be doing so much damage they won't want to get near you.

Put me in your hands, you will be godlike.
Like the previous line.

Dominate the one on ones, and the teamfights.
Again, like the previous two lines.

Nope! It's a bit deeper then that, there's a play on word thing in there you're missing.

Feel free to guess again.

Going to have to go with Radiance.

Nope!

Gonna go ahead and give a hint, to move things along. This item can be crafted into one or more other items, and part of the riddle references the item(s).

Don't think that was grammatically correct? Oh well.

er... Broadsword?

OH **** DAGON

Perhaps Iron Branch?

You gain Stats for survivability (staying safe) and for Damage/Mana/Attack Speed (put them in their place)

It builds into a Mekansm and a Pipe of Insight, both of which allow you to turn Ganks around by Healing/Nullifying Damage. This also goes for you Team.

Seems your prediction was wrong ;{)

Not Broadsword, Dagon, or Iron Branch...

one quick thing... this same thing happened with my last riddle... hmm...

I'm thinking either Mystic Staff or Hyper Stone, if I'm interpreting the riddle correctly.