D&D 5E 5E Grimlock PC

[Werebat]

Edit: except I think you'd want to define Keen Smell more fully than the MM does. In addition to the vague "you get advantage on smell checks," try giving the Grimlock a baseline capability that it can use smell checks for. A human might not have much chance of smelling a ten-minute-old scent trail on stone, no matter HOW high his Perception roll is--but maybe a Grimlock would.

I agree with this. In general, I think for any creature that has this ability, it would make sense to let it apply to Survival (tracking) checks as well as Perception checks. IOW, they get Advantage on Survival checks to track so long as some sort of scent trail is present.

Edit: The flavor text for Grimlocks pretty much says outright that they are capable of tracking by scent, so...

 

[Jester David]

Right, so maybe something like:

Ability Score Increase. Your Strength score increases by 2 and you Constitution increases by 1.
Age. Grimlocks reach adulthood in their late teens and live less than a century. However, their violent lives mean most perish before reaching middle age.
Alignment. Most grimlocks are neutral evil. The harsh subterranean world is harsh and unforgiving, and those who survive typically look after their own lives at the expense of others, and grimlocks are no exception.
Size. Grimlocks stand between 5 and 6 feet tall and average 150 pounds, being slightly smaller in stature than humans. Your size is Medium.
Speed. Your base walking speed in 30 feet,
Blind Senses. You have blindsight 30-feet. This becomes 10-feet while deafened. If unable to hear and smell this ability ceases to function.
Keen Hearing and Smell. You have proficiency in the Perception skill. Additionally, you can identify and follow creatures by their scent. Whenever you make a Wisdom (Survival) check to follow a creature whose scent you are familiar with, you are considered proficient in the Survival skill and add double your proficiency bonus to the check, instead of your normal proficiency bonus.
Stone Camouflage. You have advantage on Dexterity (Stealth) checks made to hide in rocky terrain.
Languages. You can speak Common and Undercommon, but are unable to read or write either language.

 

[Werebat]

So my player seems to want to go with a cleric of Light instead.

But I like this grimlock barbarian idea. Someday I'll have to play one. I'll name him Gug.