Alaster sits next to 4 phonetic neighbors — Alistair, Alastair, and Alexander are the closest matches by sound. Most share Alaster's Scottish cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"defender of men, protector of mankind"
"flat-bladed digging tool"
"the letter Z"
"variant of Aidan, meaning little fire"
"cup, chalice"
"heart, courageous heart"
"from the fortified city"
"whole, universal"
"king of the valley"
"open land, cleared field"
"bold land"
"holy, divine"
"meadowland, fallow land"
"foot (of Orion)"
"smooth, clear water"
"my God is Yahweh"
"great woodland clearing"
"sharp, keen, pointed"
"my angel, my envoy"
"stone sword, sword stone"
"spear wood (ash was used for spears)"
Similar sound: These names share phonetic patterns with Alaster — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Greek via Scottish Gaelic origins, giving them the same cultural heritage as Alaster.
Rhythm: Alaster is a 3-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.