Seth just plays really aggressive, you need to play a lot more defensive; matches will take a lot longer too. If you jump back and get far away, he'll just do fireballs and eventually wall jump to you (shoryuken). He's a lot easier if you can fight him and keep distance. If you @#%^ up a spinning kick (he's blocking it), he'll try to grab you afterward 90% of the time, so jump back to dodge
I beat him with almost everyone doing the same tactic, Jump in with a heavy kick, drop to a sweep then med kick or punch and a special.
And happy parrot head humping is happy.