The Dark Knight of Vanda is unarguably the toughest boss in SMRPG, putting even Smithy to shame.  Unless dying doesn't bother your or you're super confident--or you're at a ridiculously high level--don't attempt it until you have the Lazy Shells. Mario will, of course, have the weapon and Toadstool's got the armor. Mario and Geno (the third member of your party) should have the best armor you've picked up, which is probably Fuzzy clothes. It's easier with everybody at least at level 23, but if Toadstool has gotten to level 20 or 21 with the help of the Exp. Booster, I've done it with Mario and Geno as early as level 18. If you have ANY rock candy, use that up at the start of the battle before doing anything else. Toadstool should have the Frying Pan, but she'll be so busy healing Mario and Geno that she probably won't get a chance to use it until three of the Crystals are gone. Geno should have the Hand Cannon! After the Rock Candy, get off to a good start with a few Ultra Flames directed at Water Crystal and some Geno Flashes. Your first target should be Wind Crystal--she has the smallest amount of HP, so she'll kick it pretty early on if you play your cards right. After that is Earth Crystal, but only when you have a chance for regular attacks. If you Special Attack, use one that targets EVERYBODY, not just Earth Crystal. If you can time it right, the Geno Whirl is FABULOUS! But if you can't, THIS IS NOT THE TIME TO LEARN!! And if Toadstool ever gets a chance to attack rather than use Come Back, Group Hug or Therapy, do not use Psych Bomb. It's not very strong against them at all. Rather, use the Frying Pan. When Wind and Earth Crystals are both gone, turn your attentions to Water Crystal. She's strong, but just Flame her with either the Super Flame or Ultra Flame and keep on Geno Flashing. Fire Crystal is hard, but just keep pounding away! and whatever you do, don't use the Ultra Flame against him. Finally, it's Culex by himself. The Dark Star is powerful, but it can only attack one of you. The Shredder's only threatening in an abstract way, and honestly, I didn't even know it did ANYTHING until a while ago.  Now that you're alone with Culex, Toadstool will get a lot more oppurtunities to attack, but keep healing people if they need it. Keep on with Mario and Toadstool's regular attacks, and, for Geno, regular attacks or Whirls or even Blasts or Flashes, but DON'T GIVE UP!!  A popular rumour is that Culex was the final boss at the end of Final Fantasy 3, but now that I've played that game (yay!) I can tell all of you that it's not so.  The background music is very similar to the battle theme of FF6 (FF3 in America), but the analog ends there.  Isn't analog a great word?