I would suggest a 1/2 inch impact wrench. If not that, 1/2 inch breaker bar with the proper socket. With the breaker bar and an extension pipe, you can get one hell of a lot of torque.
Yep. As others have said. It's an ordinary thread so it is undone in the normal torque-direction.
I would use the correct-size 1/2" drive socket making sure I keep it pushed firmly and evenly into the recess (and thus making sure it stays squarely-held on the "plug hex") while I apply the torque.
Note: - You may need to clean the recess first! (There is nothing worse than butchered oil drain/fill plugs.)
And I'm just talking about using the "big bar" as found in "a good quality socket set". (Home-made extensions shouldn't be necessary.)
Sometimes its worth trying an imperial socket, they often fit a damaged plug better than the correct sized metric socket.. Ive had success with the grinding of the socket to improve engagement trick too..
I started by cleaning the recess that the plug sits in. Shoot with PB Blaster or Deep Creep or something just for good measure.
In my case, I got under the truck and firmly held the socket onto the plug. I put a long pipe "cheater" onto the socket handle. It extended out from under the truck where my helper gently applied the force until it loosened.