A keyed Caesar is basically an adjustment of the alphabet to put the keyword at the front without any of the repeating letters. You then pick a number to shift by and encode the message. The problem with this as with all monoalphabetic substitution ciphers is they are very vulnerable to cryptanalysis and therefore very weak ciphers.
In the interest of completion, I keyed a Caesar to “KRYPTOS” and chose a shift of 7 because there are seven letters in Kryptos.
In a cryptosystem where our expectations are often disappointed, it can be nice to have success of some kind, even if it’s a successful attempt to prove the failure of a ciphering method.
K4 remains secure.