I’ve been going overboard on these so this one will be more the intended length :p
Era’s eyes are a clock. If you look closely you’ll see they’re three different colours like a pie chart, or in this case, a clock with the spaces between the hands coloured in.
The position of the “hands” fluctuates but is also in some way different for each of Era’s schemas, sorta corresponding to the order in which his different “eras” fall. Idk, maybe the hour hand is what’s distinctive to each one and the minute and second hands move clockwise at random speeds.
….Y’know actually there are 12 main characters counting Era and a schema for each story. I actually could do it that way. Erasthemus Errator (his “humansona” he created cause he thought humans were a cool species and it would be fun to create one) could be the 12th hour.