Title says it all, what is the greatest amount of temporary hit points a character can have at one time? I think it's 45 from using Armor of Agathys with a 9th level spell slot, but is more possible?
Anything in RAW is acceptable except the following:
- Weird wishes
- Epic boons
Answers should only consider temporary hit points, not hit point mitigation methods such as polymorph, warding bond, arcane ward, etc. An ideal answer would provide the maximum one can attain by a single character's effort and the maximum attainable with the aid of others (if it's higher).
Best Answer
1030
Blackrazor (DMG, p. 216) will give you temp hp = to the max of any creature you kill. So in theory as high as you can find.
The Tarrasque (MM, p. 286) has the most potential hit points of any creature published so far, at 33d20+3301.
In any case, the Tarrasque of 5th edition has a maximum natural hit point score of 990. In addition one can apply the 2nd level abjuration spell aid using a 9th level slot to further increase the maximum hit points of the Tarrasque by 40. This makes the absolute maximum for the Tarrasque's hit points (and thus the maximum temporary hit points you could gain at once via Blackrazor) 1030. Of course, you could gain more if a more powerful creature or hit-point boosting ability were to be included in the game, but this is the most in published material.