I have not tried to beat him yet but I'm sure the only way to win is to cheese or you can pull off alot of effective combos as long as you keep dodging him.
Yes the character Shujinko changes into is random and if you don't like the person you are playing as quit the match and start again.

Dodge and use a lot of really long combos very quickly. Dodge a lot. I beat him with Li Mei and later with Tanya. It's really not that difficult.

I got lucky with Ermac, just use his weapon. Do 1,3,4,4,4 and then do a

Cheap and easy = turn the Kombat CPU strength to novice.

For some reason he seems not to defend weapons very good.
hopefully get a character you're ok with and weapon combo him again and again.
I also beat him with Ermac and his weapon combo.

I beat him with NIghtwolf using a special attack combo, heh. Just do the sweep(you know the one that pushes him away) then throw an arrow; if he starts to walk to you again do the same; in case he doesn't walk to you or jumps, throw more arrows. I had to try that 2 times but killed him eventually.

if you have milenna jus do her nine hit combo four times and he is done for.
1,1,3,L1,4,3,L1. Also you can jus press 1,1,1 over and over again until you beat him. That is how I beat him. If you have scorpion jus go to his third fighting style, and knock him in the air with your sword, then throw the spear. After that press 2,2,L1,1,3,3,L1. If you can get that combo off a couple of times then you got him beat. He is really easy if you know devasting combos with everyone in the game like I do.

play as mileena: do forward forward circle
that worked for me.
if this doesn;t help, read one of the other 5 threads with the exact same name and topic

Or You can use li mei front and or either back wind mill kicks on scorpion while he's in the air just use her flying fist moves him keep doing that and you beat him it worked for me. use the front windmill.

I kicked that Scorpion's ass with Scorpion himself. I did the 3 style combo and then used the sword move to stab Scorpion in the eye. When he reacted to the cut on his face I re-did that combo again and kept repeating. When he blocked I used a teleport kick and then a spear.

Baraka all the way. sidestep, scissors, sidestep, scissors...repeat til he's dead

liu kang
1,1,3 in his first art form
4,3,3,3 in his second
pick whichever you want to use, and stick to it, and be a cheap bastard by repeating it relentlessly. i beat him last night using the first, but each are good easy combos for this. this challenge is a bitch.

hope like hell for a character with long extensive combos, or one with a fast powerful weapon like Li Mei.(Thats how I managed to do it.) Of course once you get lucky enough to get one of these characters NEVER let up.

When I had to do that mission, they gave me Ermac. Now I have never used Ermac so far in the game so I didn't know any of his good combos. But I found one combo that was 2 hits and took up like 24% or something like that. It was short and sweet. It got me through that hard ass challenge. The combo was effective and he basically never blocked it. It works man.