Greenspawn Razorfiend (CR Help?)

[Lord Ruby34]

Greenspawn Razorfiend
Large Dragon, Lawful Evil

Armor Class:14 (natural armor)
Hit Points: 147 (16d10+48)
Speed: 50 ft., Swim 50 ft.

STR:iiiiiiiiDEX:iiiiiiiiCON:iiiiiiiiINT:iiiiiiiiWI S:iiiiiiiiCHA:
14 (+2) 19(+4) iii16 (+3)iii12 (+1)iii14 (+2)iii8 (-1)


Saving Throws: Dex +8, Con +7, Wis +6
Damage Immunities: poison
Condition Immunities: poison
Senses: Darkvision 60 ft., Passive Perception 12
Languages: Common, Draconic, Infernal
Challenge: 7


Blur of Motion: All opportunity attacks against the greenspawn razorfiend have disadvantage.

Infernal Speed: The greenspawn razorfiend may move 25 feet as a bonus action.

Improved Critical (Wingblades): When making an attack with its wingblades the greenspawn razorfiend scores a critical hit on a roll of 19 or twenty.

Soaring Assailant: As long as it does not end its turn in midair the greenspawn razorfiend may move as though it could fly.


Actions

Multiattack: The greenspawn razorfiend makes three attacks: two with its wingblades and one with its bite.

Wingblade: +8 to hit, reach 5 ft., one target, 14 (3d6+4) slashing damage

Bite: +8 to hit, reach 5 ft., one target, 9 (1d10+4) piercing damage

Poison Spit (Recharge 6): The greenspawn razorfiend spits a ball of poisonous gas that explodes upon contact with the ground. Each creature in a 15 foot radius must make a DC 14 Constitution saving throw, taking 21 (6d6) damage on a failed save, or half as much damage on a successful one.


I'd like to make sure this is a CR 7 critter, and that all my monster math is correct. This is my first attempt at homebrewing something from only a 3.5 monster and needed to adapt it to 5E.

[Ninja_Prawn]

You're not far off, I reckon. Offense comes out at CR 7, assuming you get one extra crit out of Improved Critical per three attacks (I did the maths and that's about what it amounted to).

Defense is a bit lacking. I rate it at CR 5 for 6 overall, based on an effective AC bonus of +2 from Blur of Motion. Perhaps I'm underrating that, but this thing is extremely vulnerable to Tasha's Hideous Laughter, so I don't want to give it too much credit. You could buff it up a bit with resistance to nonmagical weapons; that would increase its overall CR to 8 in one fell swoop. Alternatively, giving it full-on flight and proficiency in Wis saves (but no extra resistances) would make it 7, and cover its two biggest weaknesses.

[Lord Ruby34]

You're not far off, I reckon. Offense comes out at CR 7, assuming you get one extra crit out of Improved Critical per three attacks (I did the maths and that's about what it amounted to).

Defense is a bit lacking. I rate it at CR 5 for 6 overall, based on an effective AC bonus of +2 from Blur of Motion. Perhaps I'm underrating that, but this thing is extremely vulnerable to Tasha's Hideous Laughter, so I don't want to give it too much credit. You could buff it up a bit with resistance to nonmagical weapons; that would increase its overall CR to 8 in one fell swoop. Alternatively, giving it full-on flight and proficiency in Wis saves (but no extra resistances) would make it 7, and cover its two biggest weaknesses.

Hmm. For my group resistance to non-magical weapons wouldn't do much besides make the rogue feel bad. Fighter has a magic sword and the other melee is an OoD Paladin, and I don't want to give it flight because the 3.5 monster it was based on didn't have it. How about +1 to AC, Wis Proficiency, and two extra hit dice?

[Flashy]

You're not far off, I reckon. Offense comes out at CR 7, assuming you get one extra crit out of Improved Critical per three attacks (I did the maths and that's about what it amounted to).

Defense is a bit lacking. I rate it at CR 5 for 6 overall, based on an effective AC bonus of +2 from Blur of Motion. Perhaps I'm underrating that, but this thing is extremely vulnerable to Tasha's Hideous Laughter, so I don't want to give it too much credit. You could buff it up a bit with resistance to nonmagical weapons; that would increase its overall CR to 8 in one fell swoop. Alternatively, giving it full-on flight and proficiency in Wis saves (but no extra resistances) would make it 7, and cover its two biggest weaknesses.

I did the math just to check but as usual you're super on point. Among other things I think +2 AC is an effective way to rate Blur of Motion.


Hmm. For my group resistance to non-magical weapons wouldn't do much besides make the rogue feel bad. Fighter has a magic sword and the other melee is an OoD Paladin, and I don't want to give it flight because the 3.5 monster it was based on didn't have it. How about +1 to AC, Wis Proficiency, and two extra hit dice?

This would also work. 17 additional hitpoints, +1 AC and +2 effective AC from three or more saving throw proficiencies puts it at defensive CR 8. Overall CR is either 7 or 8 depending on whether you prefer to round up or down. Here I'd probably recommend up simply because the Improved Critical feature and slightly above average attack bonus might make it a touch swingy.

[Lord Ruby34]

Thanks guys. Should be fun to watch my group fight these things at the next session. I decided to go with two more hit dice and wis save proficiency, but no more +1 AC. Edited into the first post.