2d animation mixing

Hi,

I was making an animation for 2d character, and got a problem with mixing upper and lower body parts. I have walking animation, and attack animation, and I know there is a possible way to somehow mix them, and allow character to simultaneously walk and attack.
So, there are two ways that I know to achieve that: Splitting upper and lower body parts or using masks. But it seems like masking option in animator tab is only usefull for 3D games, not 2D.
Are there any other ways, or splitting character into pieces is normal in 2D developement?

Thanks.

Hi, I am also on the search for a bit of an explanation but from what I have found so far is in a different language. He uses a mask in the animator to create the effect you are looking for. Here is the youtube link:

Like I said, it's a Russian tutorial but you can follow along to get the idea.