If you're good enough at digging through the internet, there are some chronicles from 2012/13 about the Battle of Caldari Prime that explain this to an extent, or at least use the number in the lore to justify its presence. Some of it is in the fiction portal on the main site, but there are others that disappeared somewhere, and i don't know where.

If i recall correctly, when the older generation of clones were created, they used Sleeper implants to make them so that consciousness can be transferred from one clone to another in a way similar to Capsuleers, but more efficient and tailored for infantry use. Some troopers were unlucky enough to have their implants malfunction and have their minds taken over by the sleepers, not unlike Jamyll Sarum; except instead of going into a raving seizure-like fit, they went almost insane and went on mass killing sprees, attacking both friendly and enemy forces. Before dying due to wounds suffered at the hands of the people they attacked or by their own, they would write the number 514 in their own blood before dying completely; their consciousness destroyed by the sleepers, thus rendering them unable to be revived in a new clone.

This was colloquially known as "Going 514".

Here. Get yours Little Boy :)

Coded message from mordus legion about "new" amarian project of "undying" soldiers boyko ;p

OR

Read Ephesians 5:14

"Wake up, sleeper, rise from the dead, and Christ will shine on you." (possible too)

Choose which one you like more XD

Actually it took less than 33 but okay.

It takes 514 fucks to be given to reply to this thread with an official meaning.

You're as bad as him, I bet you say that to all the boys.

May 2014, 5/14, annoucing the end of Dust and all its playerbase !

May 30th kid. Sit down.

The only hint they ever gave about its meaning was to "look to the Caldari histories."