Which Kotal?
War God definitely loses to Gunslinger. I'm not going to say that he gets stomped out, but getting past sos4 without anything to throw back at him, is really tough(unless you're alien and you can krawl under them lol). Just about every player that I know who plays Gunslinger(Sonic, Sanix, Semiij), has great success in this match up. He can punish all swords now with his faster command grab. There are other points, I just don't want to diminish how strong Gunslinger's zoning is vs War God, by posting something that might not be that significant. He's much harder to get in on then any other character. What makes his zoning not super top is that other characters can beat out his moves with their own projectiles, due to their speed. War God just has to hold it. You could throw EX paddle toss, but you're paying resources for plus frames that may not matter at the range that you threw it.
Outside of Mystic and maybe Piercing, i'm not sure if War God has a harder match up in the game.