Ciel sits next to 5 phonetic neighbors — Siel, Cecil, and Celine are the closest matches by sound. Most share Ciel's French-origin cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"sky, heaven"
"praised, one who is praised"
"anointed one"
"song, joyful cry of praise"
"lapis lazuli, precious blue stone"
"paradise, garden of heaven"
"goddess, divine"
"auspicious, blessed"
"shining, bright one"
"beautiful flower"
"deer"
"a voyage, a day's travel, life's path"
"daughter of the sun (folkloric)"
"God has healed"
"daughter of Andrew, brave"
"successful, beloved"
"sky, celestial realm"
"bright, shining one"
"invented phonetic name"
"home ruler; powerful in work"
"torch, radiant one"
Similar sound: These names share phonetic patterns with Ciel — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have French origins, giving them the same cultural heritage as Ciel.
Rhythm: Ciel is a 1-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.