Including unofficial stats for King Grol 5e
King Grol is King of the Goblins and his stronghold is the Cragmaw Hideout.
For unofficial stats, see Stats tab below
(or Bugbear Chief on p. 33 of Monster Manual)
Use his +6 stealth to try to gain surprise on one or more of the party members to get the +2d6 damage (per attack) on the first round of combat. To get to PC's that are further away, he can throw his javelin.
Oh, and don't forget his advantage to save against a wide variety of conditions (see Stats tab below).
With his extra attack and damage, he does some decent damage to a low level party.
He's cunning enough to try to escape (remember his +6 stealth again), rather than fight to the death.
For further ideas on NPC battle tactics, see our article, Claim the Highground.