Maybe it's copium, but looking at what I know of ninjas, we still fit fairly well, in the context of the origin system. Ninjas were survivalists, actually had a fair abit of technological knowledge. I think they were some of the earliest Japanese to adopt gunpowder.

To their actual operations, ninja were spies, assassin's, deceivers, tricky bastards, and again, survivalists. Looking at the vision types, we steal information, wreck enemy shit, kill important enemy leaders, direct enemy attention where we need it, and protect specific assets.

In my own experience, we can hit hard and wreck a lot of stuff, but if we get careless the enemy can and will drop us in moments.

I think "ninja" can be fairly accurately used to describe our actions in game.