Is not Pure Evil. Never assume majority of villains being Pure Evil unless they meet the criteria. AFAIK, Heihachi hasn't done anything heinous at all. Yes, he was a villain outright, but it doesn't make him anywhere near Pure Evil whatsoever.
EDIT: I'd suggest adding a PE Proposal page before adding that kind of category. Even then Heihachi himself doesn't qualify to be Pure Evil because his acts aren't always this heinous.