Seth is completly unusable in the 1st 9 chapters, he doesnt save any turns there, He is basically a Kyle/Forde who cannot get RNG screwed.
On avererage, Kyle's 20/1 stats beat Seth's in everything except LCK and RES. He has +10.5 HP, +3.5 STR +2 SPD +3.75 DEF. Thats a pretty huge lead in some key stats.
And Forde wins everywhere except for LCK, RES, and STR. STR is only .4 less.
Personally, I wouldn't take Seth until after the other 3 paladins, but my opinion doesnt matter. You guys should take who you want.