Kain sits next to 4 phonetic neighbors — Kane, Cain, and Cane are the closest matches by sound. Most share Kain's English-origin cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"spear"
"son of Evar; son of the boar"
"goddess of the hunt and moon"
"sad, melancholy (folk etymology)"
"little fire"
"firm, unwavering"
"savior"
"slender, narrow"
"oracle, mouth of brass"
"forest guardian, one who patrols"
"castle, fortress, palace"
"God has exalted (Jah + kai)"
"descendant of Aodh (fire)"
"alder tree"
"worker in steel (occupational surname)"
"rush plant (marsh grass)"
"God is my strength, God will strengthen"
"impulsive, little king"
"servant of God"
"who is like God (via Michael)"
"reputation, esteem"
Similar sound: These names share phonetic patterns with Kain — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Hebrew origins, giving them the same cultural heritage as Kain.
Rhythm: Kain is a 1-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.