either from a form of Greek stigma/digamma (), or from a cursive variant of kappa (ϰ), which could strongly resemble a u, or by inverting Greek pi (𐍀) /p/...

supposed to be directly above the letter, not off to its upper right): ӓ  trema, diaeresis (U+0308) а̀  varia (grave accent), indicating stress on the last...