This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
俰 combines 亻 (person) with 和 (harmony, peace). The exact historical development is uncertain, but it likely relates to a person embodying harmony or softness.
A person 亻 beside 和 (harmony) suggests a gentle, harmonious person. Without a clear meaning, picture someone who brings peace and softness.
For カ, imagine a calm person humming 'kaa' like a gentle breeze, bringing harmony: kaa -> カ.