I can't remember the name of a series in which there is a god hiding in plain sight as a manservant to a former king's brother. Also I think there is an undead pirate woman who becomes the leader of a brothel. I know it's odd, but if anyone has any clues I would appreciate it. I've tried Google already.
Malazan Book of the Fallen (1999-2011) by Steven Erikson, and there's a good chance the specific book you're referring to is the fifth one, Midnight Tides (2004).
After decades of warfare, the five tribes of the Tiste Edur are united under the implacable rule of the Warlock King of the Hiroth. But the price of peace is a pact with a hidden power whose motives may be deadly. To the south, the expansionist kingdom of Lether has devoured all lesser neighbors - except the Tiste Edur.
There is a god hiding in plain sight as a manservant to a former king's brother.
From the Wikia, meet (spoilers!) Elder God of the Seas Mael:
It was revealed that Mael was secretly posing as Bugg, Tehol Beddict's manservant in Letheras. He was also Tehol's frontman in his business endeavours and proprietor of Bugg's Construction. While posing as Bugg, he was described as an old man, bald, with a wizened face and a grizzled head who squinted often.
Tehol Beddict is the brother of Brys and Hull Beddict. While Hull wasn't king, he was Sentinel, the "King's voice", but resigned.
There is an undead pirate woman who becomes the leader of a brothel.
Meet Shurq Elalle, former thief, Pirate Captain, who has an, ahem, unusual condition (she has to "engage in sexual activity" very often so that a parasite of hers is fed). This causes her to work in a brothel, where she becomes some kind of a celebrity:
Selush also "installed" a voracious ootooloo that reawakened Shurq's nerves to pleasurable feelings and brightened and reinvigorated her flesh. Shurq immediately began working in the Temple Brothel where her popularity with the clients quickly made enemies among the other women. Tehol removed her from the brothel and introduced her to the prodigious half-Tarthenal, Ublala Pung, to keep her satisfied.
Found with the Google query
fantasy book god "manservant" "undead pirate" which returned the Goodreads page. Although truth be told, the summary wasn't conclusive, but when I read Book featuring a woman who is kept alive by parasite feeding during copulation after searching this site for
[story-identification] undead pirate, I felt like it could be a match and went digging further into the Wikia.