I think the “20 Kings” (20K) followed the same route the AK took to the Blue Planet. some one posted an opinion that he thought the void history was about the WG hiding the fact they were actually pirates. I find this interesting.To be more specific, I think that the Tenryuubito are descendents of Space Pirates (SPs). First, let’s look at the Tenryuubito (CDs). Look specifically at what Saint Roswald & Saint Shalulia are wearing. Next let’s glance at Saint Charloss’ attire, as well as the unnamed CD. It’s obvious they look like astronauts so I won’t draw that correlation. In fact, I want to take you away from it, though I could point out that Oda didn’t have to illustrate the CDs to look like they were equipped to fly into outer space. No, I want to steer you away from the bubbles around their heads and focus on their clothing. Specifically look at the gauges (clock-like pieces) on their suits. Now look at the SPs that Enel fought with on the moon here & here. I looked through everyone else’s clothing in all of OP, including nobles and even the inanimate objects that had been “fed” Devil's Fruits (DFs), but only the CDs and SPs have this similarity. The only thing that comes close is Kuma’s gauge in his arm when Zoro cuts it.
Next, let’s look at the literal translation of Tenryuubito—“Heavenly Dragon Folks”. FUNimation subs uses the name “Celestial Dragons” (hence my using CD(s) as an acronym for Tenryuubito.) The crest of the CDs is called the “hoof of the soaring dragon.” ‘Heavenly’, ‘celestial’, ‘soaring’—each of these words points us skyward. Even the name Gorousei means the Five Elder Stars, again the connotation of aerial—otherworldly. Though I think the Gorousei are just the keepers of the CD secret, and not actual descendents themselves, their name, nonetheless, has “unearthly” connotations. Also, I know the SP on 440’s cover looks fox-like, but I do not suppose him to be indicative of the only SPs in the universe, especially since we see an assortment of different creatures (including humanoid) on the cover of 445.As Saint Shalulia shoots her slave she says, according to cnet’s translation, “a mere human such as yourself”, whereas Stephen translated it as, “He's just a petty HUMAN”. This is a strange thing to say, this human comment, unless it’s an indication that the CDs consider themselves as something other than human. They also all style their hair in a strange, poofy beehive. Are they, perchance, hiding some sort of antennae like the Skypieans?