The Sword of Aeschylean - Howard William G.

Kasidy Vulkner has fallen through a celestial hole in space and time that has brought her into an alternate dimension where she has an unexpected reunion with an old friend, but also encounters an old enemy.

The Venusian Galaxy's favorite rogue-The Abominable Hotfire, currently an inmate in the Bokhun Planetary Asylum for the Criminally Insane-is not living his best life.
He claims that the worst warlord in the galaxy, Diabolix, is very much alive when the everyone is convinced he's quite dead.

Meanwhile, Empress Yellowtail's only heir, Jellina, has designs on conquering the galaxy. Key to this plan of universal domination is locating the ancient device the Sword of Aeschylean, which will enable Jellina to enslave the universe. And the only being that might be able to stop her is an Abomination.