Deep As The Sky, Red As The Sea by Rita Chang-Eppig

After a Portuguese sailor kills her husband, pirate leader Shek Yeung marries his second-in-command and agrees to bear an heir to keep control of her half of the fleet. The Chinese emperor sends a brutal nobleman to clear the South China Sea of pirates and European powers plot against her, while her own retributions create fresh problems. As she balances new motherhood and command, she must decide how long to fight and at what cost.

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