Orcs – discussion about the race.

I could add, "but what if he doesn't go into Chaos after all?" and we could argue endlessly. But you probably won't find out. Against a Sylvan elf, I wouldn't invest in either anti-Chaos or anti-Haven skills. It's risky to guess, and wasting several levels on something that might not work is not our style. However, against a Warlock, anti-Chaos skills almost always work. And with a Sylvan, you need to come up with something else...