Killian sits next to 5 phonetic neighbors — Cillian, Killian, and Kelian are the closest matches by sound. Most share Killian's Irish-rooted cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"associated with the church"
"south Munster (place name)"
"God is my judge (variant of Daniel)"
"upright, fair"
"beauty, adornment, grace"
"little red one (from red hair)"
"feller of trees, hewer"
"fair, pale, bright"
"God is salvation, YHWH saves"
"from Attica, man of Athens"
"opportunity, happenstance"
"lover of churches"
"my God is Yahweh"
"whole, universal power"
"beauty, grace, excellence"
"masterless samurai"
"God prevails; God persists"
"poet"
"clay settlement, clay worker"
"hillside dweller"
Similar sound: These names share phonetic patterns with Killian — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Irish Gaelic origins, giving them the same cultural heritage as Killian.
Rhythm: Killian is a 3-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.