Kyllian sits next to 4 phonetic neighbors — Killian, Kilian, and Cillian are the closest matches by sound. Most share Kyllian's Irish-rooted cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"war, strife"
"from Arcy, Norman town"
"flowering, blooming"
"young warrior"
"ascended, elevated"
"warlike, fighter (from Thracius)"
"slender, narrow"
"man, husband"
"light, luminous"
"red-haired fighter"
"handsome, well-born"
"oarsman, rower"
"spirit of battle"
"descendant of the champion"
"little king"
"defender of men"
"from the oak grove"
"white, pure"
"cloud"
Similar sound: These names share phonetic patterns with Kyllian — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Old Irish origins, giving them the same cultural heritage as Kyllian.
Rhythm: Kyllian is a 3-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.