Kaisen sits next to 4 phonetic neighbors — Kai, Kaysen, and Mason are the closest matches by sound. Most share Kaisen's Japanese cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"continuous improvement"
"son of Otto"
"farm settlement of Dudda"
"wise protector"
"shelter, shield"
"son of the south"
"land where rye is grown"
"lover of hounds, hound-desiring"
"born of fire"
"from the roe deer land"
"shining glory"
"roof maker"
"western settlement"
"home on the wooded hill"
"God heals"
"gift of God"
"narrow, a strait"
"dweller near the heath"
"home power, ruler of work"
"strong warrior"
"father of peace"
Similar sound: These names share phonetic patterns with Kaisen — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Japanese origins, giving them the same cultural heritage as Kaisen.
Rhythm: Kaisen is a 2-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.