If you really want context, and only because it's you, you can start at http://www.nuklearpower.com/daily.php?date=080501 and read the next ~5 strips. This introduces Warmech and explains his basic motivations. When you get to the first strip without Warmech, skip on to http://www.nuklearpower.com/daily.php?date=080529 and read another ~5 strips until the next comic without Warmech to find why he was found out in the woods and the whole "completely human" bit. At this point we can pick up right at the bottom half of http://www.nuklearpower.com/daily.php?date=081014 where this particular image is from, and the page after that, and that's it. That is everything there is to know about Warmech.
If you stumble over other questions along the way ("What floating castle?" "Who are all those other guys?" "What's the deal with the temple?" "What the hell is Black Mage wearing?" etc), my best recommendation is going to have to be start at the first comic and work your way to the last. There are, however, rather a lot of them, and I won't lie to you, there are some pretty ho-hum parts.