These seem pretty cool, I especially like Godo. Corrupted Darksteel is strictly better than Darksteel Plate, so I would bump up its mana cost a bit. Also, Phyrexian Biomorph's changeling doesn't matter since it loses that ability when it becomes a copy of something else. Kondas' Retreat is very strong. It's just a better Plains in most cases. Being legendary isn't really enough of a downside, especially since you can pack your deck with legends to make it tap for a ton of mana. If you want more detailed critiques (or the real MTG fonts), just ask.
I like the flavor of your set much better than the Kamigawa block so far. The mechanics seem fun, too. I agree that corrupted darksteel is way too strong. Even just the infect/trample combo is super powerful without indestructible. Increase either the equip cost or the initial cost, or both. Godo is cool, but why not just have him equip himself, since that's what is going to happen most of the time anyway? Yofune-nushi is very strong as well. A big body + board wipe + discard effect is pretty powerful even at rare. There's nothing similar in power and effects currently that I can find. The closest might be whelming wave, and that costs 2UU just for a sorcery. The fact that it's on death is the only limitation that might keep the cost down. Also, the discard effect is squarely in black's corner, so I would consider making it UB. Maybe 2UUBB would restrict it enough to be balanced. Desolation wurm's stats aren't out of control, although trample/deathtouch is a rare combo that doesn't usually make sense to block. If you chump block to take reduced damage, your creature will be exiled and you'll still lose a land. Definitely a difficult threat to deal with, but it might be balanced. I like the phyrexian biomorph. I like the combo of different coloured phyrexian mana. Not sure how well that plays, but it's definitely interesting.
Thank you to you and Thane for the feed back. I will most likely up the cost on the corrupted darksteel. Since phyrexia is such a difficult foe, i felt it necessary that if KAmigawa is going to stand a chance, then they would have to go big or get infected. the changeling on the biomorph is intended to make it accessible to players who follow actual tribal rules. HEre is another of the new Spirit Dragons Download Attachment
The battle doesn't need a reason. The battle is its' own reason. You don't ask why a plague spreads, or a field burns. Don't ask why I fight." Quote The Black Knight, MTG