Kara, Viegraf and Cassandra are good if you like to just charge to the enemy since they almost have the same speed and they spawn at the same time... After a while, backup comes!
to beat King Krusher.. U have to grab clones and Bowser will throw orbs at you... You have to make sure that you're on the bridge... He will turn some of your clones to stone...Keep getting more clones... until there's enough to break the bridge. when he falls in the lava.. Go on one of the switches that has coins beside it. Jump to the coins.. making you reach the center.. which is where the flag...
Hope I helped somehow!