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The question isn't "Why would you want to play a goblin?" The question is, "How uncomfortable are you with your character setting himself on fire?"
Ability Score Increase. Your Dexterity score increases by 2.
Age. Goblins mature faster than other races considered fully grown at the age of 3. Unfortunately, goblins are also a very short-lived race not because of the shortness or their natural lifespan but because the majority of them live brutal and short lives or do brutal and stupid things. The oldest goblin to date was a boggart elder, who had survived to the ripe old age of 43 until he fell into a patch of bog and drowned.
Alignment. Goblins alignment tends to differ by subrace, however, it is very unlikely a goblin, regardless of subrace, will ever be lawful.
Size. Goblins are short, usually 3 to 4 feet and weigh about 50 pounds. Your size is Small.
Speed. Goblins are naturally fast despite being small creatures. Your base walking speed is 30 feet.
Darkvision. You can see in dim light within 60 feet of you as if it were bright light, and in darkness as if it were dim light. You can't discern color in darkness, only shades of gray.
Nimble Escape. Goblins know when to run when things get heated. When you are the target of an opportunity attack, you may use your reaction to impose disadvantage on that attack.
Languages. You can speak, read and write Common, and Goblin.
Subrace. Greenskins, Boggarts, Gremlins
Greenskins (Traditional Goblins)
Greenskins are what people think about when they hear the word "goblin". Their skin are shades of green or yellow, and their faces are squat and flat. These goblins are the most numerous and savage of their kin and war against anything that’s not a goblinoid. Until anything conquers and enslaves them, that is.
Ability Score Increase. You have been beaten and bruised enough to be slightly tougher than others of your kind. Your Constitution score is increased by 1.
Mud Slinger. Insults are your pastime. You gain the cantrip vicious mockery. Charisma is your spellcasting ability for this spell.
Worg Rider. Greenskins have an amicable relationship with worgs, whom they ride into battle. You have proficiency in the Animal Handling skill.
Run For It. When the odds are against you, at least you can trust your legs. When using the disengage action, difficult terrain doesn't cost you extra movement on that turn.
Boggarts (Swamp Goblins)
Boggarts are goblins that live in the swamps and marshes of the world. While they are smaller in number than greenskins, they make up for it with strong communal relationships and fierce defense of their territory. Boggarts skin range from brown to black and have little hair on their heads, though they have been known to grow beards and whiskers. Unlike their more unruly kin, Boggarts very rarely interact with other races, preferring to keep to themselves. The only race they are openly hostile against are the Bullywugs, which they are at constant war with.
Ability Score Increase. Years in the swamp has made your kind craftier than the average goblin. Your Wisdom score is increased by 1.
Bog Swimmer. Boggart hit and run tactics usually include a good dose of swimming through less than cooperative waters. You have a swimming speed of 25 feet.
Boggart Weapon Proficiency. Your clan has trained you well. You have proficiency with the blowgun and net.
Swamp Life. You have advantage on saving throws against poison and diseases, and you have resistance against poison damage.
Gremlins (Tinker Goblins)
A long time ago, a group of Rock Gnomes enslaved a clan of Goblins that had been marauding in their territory. The descendants of these Goblins are known today as Gremlins. Gremlins are unlike the rest of their race, they have long noses unlike the usual squat noses of goblinoids, skin that ranges from turquoise to red, and some hair on their body. They are incredibly intelligent for goblins and have a passion for creating that matches even the most dedicated of gnomes. Unfortunately, this passion is for creating things that destroy, which puts the goblins in a vicious cycle of rebuilding and destroying. They are the fewest among the goblins mostly because of their mad experiments. The main cause of death among gremlins is "immolation".
Ability Score Increase. You may not have a fiber of common sense in your little red body, but that doesn't mean you're not a genius! Your Intelligence Score is increased by 1.
Almost Fire Proof. You have set yourself on fire so often you've gotten used to it. You are resistant to fire damage.
Tinkerer. You count as a tinker gnome for all feats.
Dangerous Tinker. The gnomes like pretty things, but you like your creations to be a little more dynamic. You have proficiency with one artisan’s tool of your choice. Using those tools, you can spend 1 hour and 10gp worth of materials to construct a Tiny clockwork device (AC 5, 1 hp) that works for 24 hours, or when you use your action to dismantle it. You can have up to three such devices active at one time. You may reclaim the parts used to create the device once it stops functioning, only if it did not explode. When you create a device, choose one of the following options:
- Arsonist's Friend: A small brass rod with a slit at the top and a button on the side. When the button on the device is pushed roll 1d6. On a roll of 2-6, the device produces a miniature flame, which you can use to light a candle, torch, or campfire. On a roll of 1, the device explodes causing 1d4 fire damage to the user.
- Blast Orb: The device is a small brass orb that makes a ticking sound once a small button on the top is pressed. One round after the button at the top is pressed the device explodes in a 5-foot radius dealing 1d8 fire damage to anything within it. If the device is destroyed, nothing happens.
- Bomb Boy: A clockwork tiny construct that is in the form of a goblin. When placed on the ground, the toy moves 5 feet across the ground on each of your turns in the direction it is facing making a loud wailing sound as it walks. When it is destroyed roll a d20. On a roll of 12 or higher, the object explodes in a sphere five feet in diameter dealing 1d4 piercing damage.