With every minor Breakthrough of a demigod, one Extra kill becomes an Extra+ Skill, while with two such breakthroughs, an Extra Skill becomes a Unique Skill. The process continued as such.
This was something considered the blessing of the World, thus there would be no sub-skills for evolving Skills using such a process.
In some cases, there are those who don't recieve a divine skill until they broke through a major realm, gaining a Unique+ skill. This was Alfredo's case, when he became a Demigod.
And the more special ones, might not gain one until they broke through two major realms, gaining a Divine Skill by then, making them fortunate.
Now, the main point of this conversation, was to tell you how a demigod like himself, peak, with two Divine Skills and couple Unique Skills could only reach the 5th floor. Just like today, that was what he expected.