The Sentinel

The Sentinel by Troy Denning is book five in The Sundering (series).

Summary
"Embittered paladin Kleef Kenric is on a quest to stop evil forces from taking advantage of the chaos rolling across the land of Faerûn and claiming dominion over the entirety of the Realms. Stubbornly clinging to his family's worship of a long-forgotten god, Kleef Kenric soon discovers that his god has blessed him with divine gifts, making him one of a new group of Chosen cropping up around the Realms. This divine gift makes him an excellent ally--and a target for those who wish corral his powers. After battling his way out Marsember, a city besieged on all sides in the wake of the Sundering, he becomes swept up in the mission of a group of odd allies--a warrior noblewoman, an accomplished thief, and a mysterious short pudgy man exuding a faint odor of decay. With the forces of Shade tracking their every step, they travel to the Underdark to thwart the rise of the goddess of Death, but before long Kleef learns that his allies hide dangerous secrets--secrets that could destroy not only Kleef but the very fabric of the Forgotten Realms."

Kleef Kenric, a Topsword of Marsember, is aiding in the evacuation of his city before an imminent shadovar attack, during which he takes up the defense of Arietta Seasilver, Joelle Emmeline and Malik.

Joelle and Malik are transporting the Eye of Gruumsh, an orc holy artifact, for Sune as a gift from Luthic to Grumbar - who are secret lovers - in order to convince the primordial not to abandon Toril, whose absence will make it easier for Shar to infuse Toril with the Shadowfell. Malik is aiding Joelle, posing as a Chosen of Myrkul, though he is still the Chosen of Cyric.

Along the way to a temple to Grumbar in the Underchasm, Kleef, one of Helm's few living worshipers, discovers that he suddenly has the powers of a Chosen as well. Arietta, who believes she is the chosen of Siamorphe, is charmed by Joelle into falling in love with her, as in order for Grumbar to recieve the Eye, a ritual must be performed that requires the death of someone for the person they love.