I would like to create a character built around these three concepts.

1. My word is my bond and I will never break it
2. The world will founder with order and disciple
3. The law is hard but it is the law

I am thinking that this character is a High Elf whose child had been inflicted with lycanthropy. This character; being a Sage and loving their child more than anything in the world, dedicated their life to finding a cure. They spent centuries searching.  One full moon however, they made a mistake. They failed to properly secure the cell in which they would lock their child during the full moon. The child escaped and in their uncontrolled state, killed several people and infected several others as well before escaping into the Forrest.

So we have a High Elf, Lawful Good sage who was forced to kill his own child because "the law is hard but it is the law."

We also have a little bit of background there.

Can you please help me flesh this character out into something playable?  This character doesn't have to be a sage, I just thought sage because of all the research they have done into finding a cure for lycanthropy.  Also, I would consider other races if they fit better thematically but I do want the to be Lawful Good.

Cheers

jay

Hi SocialFoxes o/

The first thing that comes to mind would be a Paladin, more specifically an Oath of Conquest one.
Oath of Conquest, albeit its tenets can be interpreted in a certain way, does not necessarily means the character is what could be perceived as "evil", on the contrary, it's basically Judge Dredd.
The only problem I can see with this and with the 3 concepts you want, is that it would not really fit a Lawful Good alignment, but rather be more fitting a Lawful Neutral character.
Lawful Good characters follow the rules but always to do something benefiting others, as they interpret the law in a way that always favors the weak.
Lawful Neutral characters, on the other hand, apply the law as it is in any given scenario, regardless of possible factors not taken into consideration by the law itself that might change the interpretation of it. As I said above, Judge Dredd basically (or any Warhammer 40k Arbitrer worthy of its name, to give another comparison).

You could work around it by making your character the head of a community, this way the weight of the authority and to lead by example could bring even a LG character to make a hard choice for the greater good of the whole community.
In this case a Paladin of the Oath of the Crown would be really fitting.

In the end, I think the best class is Paladin, either Oath of the Crown or Oath of conquest (which are basically two sides of the very same coin), depending on which side you want to play on more and what alignment appeals to you the most (I guess LG :) ). Race-wise, High Elf is a perfectly reasonable choice, as good as any other while not "the best" for a Paladin (but this game is not about optimisation unless you want it to be).

Hope this helps :)

A paladin is a great way to go, but if you want to play something outside of the box:

Barbarian: Either the Path of the Ancestral Guardian (From a strict, lawful culture. Your spirits are cold remorseless judges) or Path of the Zealot (You worship Law rather than a divinity.) Your rages could represent either your anger at others disregarding the law when you had to kill your son to uphold it or sinking into a state of emotionless judgment. You could also play the Path of the Totem Warrior (Wolf) if your son inherited lycanthropy from you or you ancestors.

Cleric: Recast the Knowledge Domain as the Law Domain. If you want to play a more “smite-y” character, and your DM is cool with it maybe swap out the 1st level features for those of the Storm Domain (Thunder damage is The Word of Law) as well as Potent Spellcasting for Divine Strike.

Fighter: You can probably role play any class as a champion for law, but it might be interesting to ask your DM if you can play an Eldritch Knight, but instead use spells from Divination and Evocation (Arcane Vigilante), Divination and Abjuration (Protector of the truely Inocent) or Divination and Necromancy (Death is the final arbiter.)

Ranger: The Hunter archetype specifically states that you stand as a bulwark between civilization (law) and wilderness (chaos) and the Monster Slayer fits thematically with your desire to rid the world of lycanthropy. Both retain the “elves connection to nature” and could be played as an Old West Marshal style character, hunting down law breakers and bringing them to (or meting out) justice.

Rogue: You could play an Inquisitor, in either the Sherlock Holmes “law is logic” sense or “any violation of the law demands punishment” Inquisition sense (probably less lawful good), just reskin Sneak Attack as Swift Justice (and maybe learn a different language instead of Thieves’ Can’t)

Sorcerer: The Divine Soul lets you choose an affinity with Law as well as chose from the Cleric spell list when you learn spells so you can curate your spell list to fit your obsession with law (Zone of Truth comes to mind.)

Warlock: As a warlock of The Celestial your patron could be an Archon, you could reflavor the Hexblade as a hunter of justice, or your pact with The Fiend (or a vengeful, lawful power) could be an agreement to punish those who break the law. Use your spells and invocations to further flesh out your belief that the law is the law.

You could also consider the Folk Hero background and consider how your community’s praise for ridding them of the menace of your son conflicts with your guilt from killing him or make up an Outcast background with Skill, Tool and/or Language Proficiencies from the culture that threw you out when you did what you believed you had to with the Wanderer feature from the Outlander background.

Dramatic twist: Your son wasn’t guilty, the only reason you couldn’t find a cure was because he was of the Lythari and not afflicted with normal lycanthropy. He was framed by an actual werewolf...who is still out there.