Harold loves explosives, the smell of cordite, and the dull thump of an underground detonation. Grenades or traps, it's all the same to him. He'll plant them, throw them or disarm them. He's earned the nickname "unbreakable", because despite several serious accidents, and living over a hundred years, he never seems to die.
Harold has some notable deviations from the rules, and is in some ways an incredibly powerful character. Starting at level 11, Harold has 4 perks, despite being a ghoul with a Perk Rate of 4, meaning that by level 11, he should only have two perks (3 at level 12, and then a 4th at level 16).
At level 12, he will gain a 5th perk, and can be used to take Mutate! in order to replace Skilled with Gifted, significantly raising all Harold's stats, while still have gotten the benefit of having skilled up until level 11, without any drawback, due to the extra perks. In fact, at level 12, gaining his 5th perk, he would still have more perks than a standard Human with a Perk Rate of 3, who gain their 4th perk at level 12. This is arguably balanced by the fact that the 4 perks that he has can be considered less than stellar; Die Hard, Rad Child, Bonsai, and Way of the Fruit.
Harold also has 4 tagged skills, without having taken the Tag! Perk, meaning that when he would take Tag!, he would have a total of 5 tagged skills, and as opposed to the perks, none of his tags can be considered sub-par. The negative part is that he lacks the Fast Shot trait, integral for a dedicated thrower.
Harold already has 10 points in Big Guns, but has otherwise only spent points in tagged skills, making it a good contender for the Tag! perk, but ghouls do very badly with heavy weapons.
Harold also has two stat points more than he should have.
This Harold appears only in Fallout Tactics. Even though he shares the name with a certain other ghoul-like mutant, and has a tree growing out from his head just like him, he probably is just an homage to that character.