It's a little scary I must admit. Scorpion really knows how to turn on the
heat against Kenshi and the main thing I aim for is to have the right
balance between aggression and defense. Your best friend is your armor with EXrk and throws. When he teleports try to catch him with EXrk, next time expect an empty teleport and go for a throw. Try to avoid tele slice because it's generally too slow and they can teleport on reaction and full combo punish. Go for pokes to try to disrupt scorpion. When you start to get the beat on him, don't stop! Pressure the shit out of him but try to do a lot of fake charges and jump overs and use your ji1 because it has so much reach and is very fast and can catch him when he goes to teleport... sometimes anyway. Also try just running up and nj on the spot because a lot of scorpion like teleporting on wake up.
Telepush is nice because scorpion really likes that mid to far distance kinda field. If you block his overhead minion try to hit him with tele slash but I'm not to sure you can catch him in time like you can with Kenjustu's tele grab. Something that I love to do is purposefully whiff kick the air like you dropped teleslash and punish their attempt to punish your "drop". Be careful though, this shit is unsafe against scropions zoning. Against Hell fire make sure to use your reflects to catch them (no fireballs for you) out and if you can convert it into teleslash- watch out for cancels though. You gotta be active again against Hellfire because that unblockable fire move but it's very unsafe. You can kinda wreck scorpion whenever he trys to flame aura with your specials... sucks to be Hellfire scorpion. And if he does it when he knocks you down you probably want to either jump on the spot when the pressure or teleport happens or use EXrk to armor out or maybe go for a poke but I wouldn't really try it. Sometimes it's also a good idea to use teleslash at fairly close rang because a lot of people won't expect it but It's usually unsafe.
You just don't want to play their game! When you feel like they are starting to go on the defensive and react better to your aggression go back to your zoning roots. Make sure to use your pokes focus d4 and b1 is pretty move also, most of your straight up zoning won't really work but if your aggression game is sharpened and you know how to duke them out you should be fine.
Raiden though...
P.S. I play a lot more Kenjutsu so if my advice isn't very sound I apologize