Unfortunately,the word particular has multiple meanings(1.Specific / distinct 2.Noteworthy / exceptional), and its exact meaning depends on context and what it's describing....

I feel the same way! Grammatically, "that" should be considered a conjunction.

That sentence really reads like a metaphor for how power works—"the fat cats learned to harmonize" implies that once the elites stopped competing and started collaborating, they quietly consolidated control. And then "took over the world" not through force, but through coordination