Skylark Series/YMMV


 * Designated Hero: The Kondalians have practically no traits that would be considered sympathetic by modern readers. They have no concept of democracy, race-based slavery is unquestioned, they've been at war for 6000 years over ideology, are Social Darwinists who believe themselves a Superior Species, and admit to having no concept of mercy. All in all, they are no better than the Mardonalians; the only reason they are considered good is because they were nice to the heroes.
 * Unlike the Mardonalians, and the villains generally in the series, the Kondalians are not Absolute Xenophobes, but willing to co-operate peacefully with other planets. That said, they are typically portrayed as a species of Proud Warrior Race Guys, with a strong whiff of Barsoom. They're very flawed good guys, and they do occasionally get called out on their warmongering by the human protagonists.
 * Magnificent Bastard: DuQuesne.
 * Older Than They Think: A "dark star", essentially a black hole, and mushroom clouds produced by the atomic/total conversion of explosive shells. Both in The Skylark of Space, published in 1928.
 * Early drafts are said to go all the way back to 1916. That is sixty years before Star Wars.