Только когда я добралась до оригинала SnowCrash, до меня (и то, с изрядным опозданием), дошло, почему имя создателя Черного Солнца пишется именно так, как пишется: Да5ид. По русскому переводу об этом сложно догадаться из-за специфики алфавита. А вот когда перед глазами оригинальный текст...
В общем, смотрите:

Juanita went celibate for a while and then started going out with Da5id and eventually got married to him. Da5id had no doubts whatsoever about his standing in the world. His folks were Russian Jews from Brooklyn and had lived in the same brownstone for seventy years after coming from a village in Latvia where they had lived for five hundred years; with a Torah on his lap, he could trace his bloodlines all the way back to Adam and Eve. He was an only child who had always been first in his class in everything, and when he got his master's in computer science from Stanford, he went out and started his own company with about as much fuss as Hiro's dad used to exhibit in renting out a new P.O. box when they moved. Then he got rich, and now he runs The Black Sun. Da5id has always been certain of everything.

Если посмотреть на английский текст, то можно достроить недостающий кусочек имени.
Da5id -> David (римское V соответствует арабоскому 5).