Seg the Bowman — Alan Burt Akers

Here's a special treat for everyone who loves novels of high adventure on exotic worlds in the tradition of Burroughs and Norman. For this is such a novel, complete in itself, of Dray Prescot's fighting comrade, Seg, the finest archer of two worlds. Seg is a wild and reckless fellow, courageous in the face of any adversity, and this is the account of his greatest challenge.

Single-handed, on an enemy island, Seg becomes knight-protector of the mysterious lady Milsi, and by her side, beats off frightful beasts and inhuman foemen intent on blocking her path to a rightful royal inheritance.

It's action science fiction, heroic fantasy, and high romance under the twin suns of Antares in Scorpio.