I created a new character for a game last night, a Scourge Aasimar Grave Domain Cleric, while reviewing my spells and abilities I came across this special feature. However I did not see a limit to it making it seem rather OP. Would anyone be able to explain it better to those that have also come across it?
Circle of Mortality (Special)
You restore maximum HP (instead of rolling the dice) with healing spells to a creature with 0 HP.You learn the spare the dying cantrip, can cast it as a bonus action, and it has a range of 30 ft.
Is the term "maximum HP" the source of the confusion? It may be that the wording for the quick-reference blurb is unintentionally misleading. The proper text is much clearer (you can click/tap the ability name on your character sheet to see the full text on the sidebar):
"When you would normally roll one or more dice to restore hit points with a spell to a creature at 0 hit points, you instead use the highest number possible for each die."
For example, casting a Cure Wounds with a 2nd level slot would normally have you roll 2d8 and add your spellcasting modifier (Wisdom for cleric) to come up with the number of hit points your target would recover. With Circle of Mortality, that calculation becomes "16 + wisdom modifier" if your target is at 0 hp.
Ohh so it's not Maximum HP of the PC but of the spell being cast, that makes it less OP, thank you for clearing up the confusion. I honestly thought it was for the PC's full health and I just thought to myself welp... GG DM