If KoT enters battle after Martha, then he would not negate. If, however, KoT is in battle first (say if Martha is banded in later), he would prevent Martha's ability. Since "negate" means "interrupt and prevent" Martha can still be prevented even though she can't be interrupted.
At least, that's usually the case. I don't remember their effects offhand and I can't seem to get to the REG to verify.
