Heart of St. Bathus 5E

Heart of St. Bathus
Borne by a Paladin,
Stolen by a Demon - Lost in Darknessss
Long ago, a bold paladin sought the same glory as his celebrated ancestors, but in a moment of weakness he gave up his own soul in exchange for success in battle. He now lies suspended between life and death, and his soul is lost. It's up to the adventurers to find it and redeem a fallen paladin while facing the wrath of a powerful demon lord in the process.
Heart of St. Bathus is a sandbox-style campaign for 5e roleplaying designed to take a party of characters from Level 3 (Tier 1) to Level 12 (Tier 3). Answering an appeal for aid from the monks of Goodheart Abbey, the adventurers set off in search of a famed paladin's lost soul, venturing first to a cursed fortress and then into the labyrinthine depths beneath. But it's far from a simple mission: The soul - and the heart-shaped jewel to which it is bound - have been stolen by a cunning devil who has taken it to her citadel far below within the twisting passages of the Under Realms. And the Heart's true master, an imprisoned demon lord, lurks in the darkest corners of the realm, hoping to use the unwitting adventurers to aid in his escape.
The soul of a brave paladin hangs in the balance as the adventurers delve into dark and unknown regions!A detailed overview of an entirely new and unexplored section of the Under-Realms, with its own unique inhabitants, factions, and creatures. Your players will find their swords and wits challenged as diplomacy and guile are sometimes as important as combat and tactics.
Extensive maps of 20+ fascinating locations, including subterranean settlements, fortresses, temples, and cave complexes.
New monsters and NPCs suitable for any campaign.
Full-color illustrations and maps
From William Kenower, author of Lost City of Barakus

If your campaign takes place in the Lost Lands, Heart of St. Bathus begins in the Grand Duchy of Reme, in the Duchy of Westmarch's capital of Eckland.