It is impressive, purely from a technical standpoint. I don't really approve of tattoos, but from what I understand of how they're done, and how the ink reacts with skin, the tattoo artist clearly has a lot of talent to get that kind of vivid color and detail.
I wouldn't ever get anything like it, partially because tattoos are against my religion, but partially because like people have said-- it's your entire back, and when you get old, and wrinkly, that's going to look terrible. If I were going to throw down for a Warhammer tattoo of some sort, I'd settle for an aquila or an icon of Chaos on a bicep or something, and have it be small-ish.
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