>>22760140It's a combination of shared design elements and personality/content traits. Relevant Lamy attributes include:
Highly detailed eyes
One bright color dominating the design with white as an accent color
Highly skilled at Zatsudan
Easy to listen to and distinctive voice
ASMR as a recurring content type
Above average intelligence
A desire to provide support to their fans by occupying a role in their life (Onee-san/Wife/Mama/Girlfriend)
Large bust
If a Holo has enough of these attributes (with particular emphasis being put on design elements) they are classified as a Lamy.