Shovel Knight: Specter of Torment

My favourite strategy is to combine the Raiment of Risk and the Chronos Coin (see Spec'd Out). The goal is to slow time with the Chronos Coin and get in close to do a lot of standing swings as quickly as possible. I find Plague Knight and King Knight to be especially good targets for this because of their very predictable jump arc at the beginning of their fights. Polar Knight is also really predictable, too. Just be aware of when your Chronos Coin is about to wear off (there is an audio cue). At that point, either back away to safety or activate another coin. If you can't finish them off with one use of the Coin, a second should do the job. If you accidentally take a hit, you can let yourself die and try again from a checkpoint. I would usually destroy a checkpoint earlier on in the stage to activate the Raiment of Risk and keep the checkpoint right before the boss as a backup in case I failed. If I failed again, I would usually just restart the stage but it is up to you if you want to do that or try again from an earlier checkpoint.

Here is a video example of Untouched on Polar Knight and King Knight: