5E: Converting AD&D Monsters to Fifth Edition

[Casimir Liber]

ok sounds good

 

[Cleon]

ok sounds good

Assuming its round's attacks are three Fiery Falchions for 29½ damage each, plus a 14 damage bonus action, a 9 damage Reaction, Legendaries worth 18 damage and it's set two opponents on fire for 11 damage, which adds up to a 140½ DPR.

Running the numbers through the CR Calculator the firelord came out exactly on the cusp of CR 19 and CR 20.

According to the Calc, it's Offensive CR 21 and Defensive CR 17, which comes to Challenge Rating 19, but if the DPR is 141 then its OffCR becomes 22 and the overall CR 20.

However, the Monster Features option has stopped working, so I wasn't able to make allowances for its protective abilities of Magic Resistance or Purifying Flame. Since those will likely increase the DefCR to 18 or 19, I feel that makes the firelord a better fit to Challenge Rating 20.

 

[Casimir Liber]

Sounds good to me - no change in PB from 19 to 20 so no adjusting needed otherwise