This card is a common from the Struggle of Chaos set. Because it's so interesting, I'm going to go ahead and explain the Struggle of Chaos set.
In Struggle of Chaos, there is a basic theme revolving around something of a war between dragons, humans, and demons. Because of this, all of the monsters in the set are dragon, demon, or warrior class(with a tiny bit of magicians). There are plenty of cards in this set that support all of these classes, and there are also plenty of cards that are meant to pick out and destroy these classes. Troop Commander is one example of a support card.
So, what makes this little guy great? First of all, there's the special summon ability. The special summoning ability alone makes Troop Commander a quick, efficient card. By breaking the one-monster-per-turn rule, you can have sacrificial fodder for that Blue-Eyes in no time.
However, an even cooler part about this card is that if you have two Troop Commanders in play and no monsters that aren't of the warrior class, your opponent can't attack. This makes Troop Commander a sort of combo-based permanent Sealing Swords of Light in a Warrior Deck. Of course, you could always add "A Mind that Reflects as Water"(discussed with Card #2) to the mix, and you get the same results.
On a final note, one thing that I'm trying to hint at with most of these card discussions is that in the Japanese sets there are many amazing common cards. The last three discussed cards have all been commons, and they are all so powerful that you could probably base your entire deck around them. As a matter of fact, it's harder to use many Japanese rares than it is the commons.
Well, that's a wrap. I hope you enjoyed this one...maybe I'll do a rare next time. ^_^
